xref: /openbmc/qemu/tests/qtest/microbit-test.c (revision 139c1837)
1 /*
2  * QTest testcase for Microbit board using the Nordic Semiconductor nRF51 SoC.
3  *
4  * nRF51:
5  * Reference Manual: http://infocenter.nordicsemi.com/pdf/nRF51_RM_v3.0.pdf
6  * Product Spec: http://infocenter.nordicsemi.com/pdf/nRF51822_PS_v3.1.pdf
7  *
8  * Microbit Board: http://microbit.org/
9  *
10  * Copyright 2018 Steffen Görtz <contrib@steffen-goertz.de>
11  *
12  * This code is licensed under the GPL version 2 or later.  See
13  * the COPYING file in the top-level directory.
14  */
15 
16 
17 #include "qemu/osdep.h"
18 #include "exec/hwaddr.h"
19 #include "libqtest.h"
20 
21 #include "hw/arm/nrf51.h"
22 #include "hw/char/nrf51_uart.h"
23 #include "hw/gpio/nrf51_gpio.h"
24 #include "hw/nvram/nrf51_nvm.h"
25 #include "hw/timer/nrf51_timer.h"
26 #include "hw/i2c/microbit_i2c.h"
27 
28 static bool uart_wait_for_event(QTestState *qts, uint32_t event_addr)
29 {
30     time_t now, start = time(NULL);
31 
32     while (true) {
33         if (qtest_readl(qts, event_addr) == 1) {
34             qtest_writel(qts, event_addr, 0x00);
35             return true;
36         }
37 
38         /* Wait at most 10 minutes */
39         now = time(NULL);
40         if (now - start > 600) {
41             break;
42         }
43         g_usleep(10000);
44     }
45 
46     return false;
47 }
48 
49 static void uart_rw_to_rxd(QTestState *qts, int sock_fd, const char *in,
50                            char *out)
51 {
52     int i, in_len = strlen(in);
53 
54     g_assert_true(write(sock_fd, in, in_len) == in_len);
55     for (i = 0; i < in_len; i++) {
56         g_assert_true(uart_wait_for_event(qts, NRF51_UART_BASE +
57                                                A_UART_RXDRDY));
58         out[i] = qtest_readl(qts, NRF51_UART_BASE + A_UART_RXD);
59     }
60     out[i] = '\0';
61 }
62 
63 static void uart_w_to_txd(QTestState *qts, const char *in)
64 {
65     int i, in_len = strlen(in);
66 
67     for (i = 0; i < in_len; i++) {
68         qtest_writel(qts, NRF51_UART_BASE + A_UART_TXD, in[i]);
69         g_assert_true(uart_wait_for_event(qts, NRF51_UART_BASE +
70                                                A_UART_TXDRDY));
71     }
72 }
73 
74 static void test_nrf51_uart(void)
75 {
76     int sock_fd;
77     char s[10];
78     QTestState *qts = qtest_init_with_serial("-M microbit", &sock_fd);
79 
80     g_assert_true(write(sock_fd, "c", 1) == 1);
81     g_assert_cmphex(qtest_readl(qts, NRF51_UART_BASE + A_UART_RXD), ==, 0x00);
82 
83     qtest_writel(qts, NRF51_UART_BASE + A_UART_ENABLE, 0x04);
84     qtest_writel(qts, NRF51_UART_BASE + A_UART_STARTRX, 0x01);
85 
86     g_assert_true(uart_wait_for_event(qts, NRF51_UART_BASE + A_UART_RXDRDY));
87     qtest_writel(qts, NRF51_UART_BASE + A_UART_RXDRDY, 0x00);
88     g_assert_cmphex(qtest_readl(qts, NRF51_UART_BASE + A_UART_RXD), ==, 'c');
89 
90     qtest_writel(qts, NRF51_UART_BASE + A_UART_INTENSET, 0x04);
91     g_assert_cmphex(qtest_readl(qts, NRF51_UART_BASE + A_UART_INTEN), ==, 0x04);
92     qtest_writel(qts, NRF51_UART_BASE + A_UART_INTENCLR, 0x04);
93     g_assert_cmphex(qtest_readl(qts, NRF51_UART_BASE + A_UART_INTEN), ==, 0x00);
94 
95     uart_rw_to_rxd(qts, sock_fd, "hello", s);
96     g_assert_true(memcmp(s, "hello", 5) == 0);
97 
98     qtest_writel(qts, NRF51_UART_BASE + A_UART_STARTTX, 0x01);
99     uart_w_to_txd(qts, "d");
100     g_assert_true(read(sock_fd, s, 10) == 1);
101     g_assert_cmphex(s[0], ==, 'd');
102 
103     qtest_writel(qts, NRF51_UART_BASE + A_UART_SUSPEND, 0x01);
104     qtest_writel(qts, NRF51_UART_BASE + A_UART_TXD, 'h');
105     qtest_writel(qts, NRF51_UART_BASE + A_UART_STARTTX, 0x01);
106     uart_w_to_txd(qts, "world");
107     g_assert_true(read(sock_fd, s, 10) == 5);
108     g_assert_true(memcmp(s, "world", 5) == 0);
109 
110     close(sock_fd);
111 
112     qtest_quit(qts);
113 }
114 
115 /* Read a byte from I2C device at @addr from register @reg */
116 static uint32_t i2c_read_byte(QTestState *qts, uint32_t addr, uint32_t reg)
117 {
118     uint32_t val;
119 
120     qtest_writel(qts, NRF51_TWI_BASE + NRF51_TWI_REG_ADDRESS, addr);
121     qtest_writel(qts, NRF51_TWI_BASE + NRF51_TWI_TASK_STARTTX, 1);
122     qtest_writel(qts, NRF51_TWI_BASE + NRF51_TWI_REG_TXD, reg);
123     val = qtest_readl(qts, NRF51_TWI_BASE + NRF51_TWI_EVENT_TXDSENT);
124     g_assert_cmpuint(val, ==, 1);
125     qtest_writel(qts, NRF51_TWI_BASE + NRF51_TWI_TASK_STOP, 1);
126 
127     qtest_writel(qts, NRF51_TWI_BASE + NRF51_TWI_TASK_STARTRX, 1);
128     val = qtest_readl(qts, NRF51_TWI_BASE + NRF51_TWI_EVENT_RXDREADY);
129     g_assert_cmpuint(val, ==, 1);
130     val = qtest_readl(qts, NRF51_TWI_BASE + NRF51_TWI_REG_RXD);
131     qtest_writel(qts, NRF51_TWI_BASE + NRF51_TWI_TASK_STOP, 1);
132 
133     return val;
134 }
135 
136 static void test_microbit_i2c(void)
137 {
138     uint32_t val;
139     QTestState *qts = qtest_init("-M microbit");
140 
141     /* We don't program pins/irqs but at least enable the device */
142     qtest_writel(qts, NRF51_TWI_BASE + NRF51_TWI_REG_ENABLE, 5);
143 
144     /* MMA8653 magnetometer detection */
145     val = i2c_read_byte(qts, 0x3A, 0x0D);
146     g_assert_cmpuint(val, ==, 0x5A);
147 
148     val = i2c_read_byte(qts, 0x3A, 0x0D);
149     g_assert_cmpuint(val, ==, 0x5A);
150 
151     /* LSM303 accelerometer detection */
152     val = i2c_read_byte(qts, 0x3C, 0x4F);
153     g_assert_cmpuint(val, ==, 0x40);
154 
155     qtest_writel(qts, NRF51_TWI_BASE + NRF51_TWI_REG_ENABLE, 0);
156 
157     qtest_quit(qts);
158 }
159 
160 #define FLASH_SIZE          (256 * NRF51_PAGE_SIZE)
161 
162 static void fill_and_erase(QTestState *qts, hwaddr base, hwaddr size,
163                            uint32_t address_reg)
164 {
165     hwaddr i;
166 
167     /* Erase Page */
168     qtest_writel(qts, NRF51_NVMC_BASE + NRF51_NVMC_CONFIG, 0x02);
169     qtest_writel(qts, NRF51_NVMC_BASE + address_reg, base);
170     qtest_writel(qts, NRF51_NVMC_BASE + NRF51_NVMC_CONFIG, 0x00);
171 
172     /* Check memory */
173     for (i = 0; i < size / 4; i++) {
174         g_assert_cmpuint(qtest_readl(qts, base + i * 4), ==, 0xFFFFFFFF);
175     }
176 
177     /* Fill memory */
178     qtest_writel(qts, NRF51_NVMC_BASE + NRF51_NVMC_CONFIG, 0x01);
179     for (i = 0; i < size / 4; i++) {
180         qtest_writel(qts, base + i * 4, i);
181         g_assert_cmpuint(qtest_readl(qts, base + i * 4), ==, i);
182     }
183     qtest_writel(qts, NRF51_NVMC_BASE + NRF51_NVMC_CONFIG, 0x00);
184 }
185 
186 static void test_nrf51_nvmc(void)
187 {
188     uint32_t value;
189     hwaddr i;
190     QTestState *qts = qtest_init("-M microbit");
191 
192     /* Test always ready */
193     value = qtest_readl(qts, NRF51_NVMC_BASE + NRF51_NVMC_READY);
194     g_assert_cmpuint(value & 0x01, ==, 0x01);
195 
196     /* Test write-read config register */
197     qtest_writel(qts, NRF51_NVMC_BASE + NRF51_NVMC_CONFIG, 0x03);
198     g_assert_cmpuint(qtest_readl(qts, NRF51_NVMC_BASE + NRF51_NVMC_CONFIG),
199                      ==, 0x03);
200     qtest_writel(qts, NRF51_NVMC_BASE + NRF51_NVMC_CONFIG, 0x00);
201     g_assert_cmpuint(qtest_readl(qts, NRF51_NVMC_BASE + NRF51_NVMC_CONFIG),
202                      ==, 0x00);
203 
204     /* Test PCR0 */
205     fill_and_erase(qts, NRF51_FLASH_BASE, NRF51_PAGE_SIZE,
206                    NRF51_NVMC_ERASEPCR0);
207     fill_and_erase(qts, NRF51_FLASH_BASE + NRF51_PAGE_SIZE,
208                    NRF51_PAGE_SIZE, NRF51_NVMC_ERASEPCR0);
209 
210     /* Test PCR1 */
211     fill_and_erase(qts, NRF51_FLASH_BASE, NRF51_PAGE_SIZE,
212                    NRF51_NVMC_ERASEPCR1);
213     fill_and_erase(qts, NRF51_FLASH_BASE + NRF51_PAGE_SIZE,
214                    NRF51_PAGE_SIZE, NRF51_NVMC_ERASEPCR1);
215 
216     /* Erase all */
217     qtest_writel(qts, NRF51_NVMC_BASE + NRF51_NVMC_CONFIG, 0x02);
218     qtest_writel(qts, NRF51_NVMC_BASE + NRF51_NVMC_ERASEALL, 0x01);
219     qtest_writel(qts, NRF51_NVMC_BASE + NRF51_NVMC_CONFIG, 0x00);
220 
221     qtest_writel(qts, NRF51_NVMC_BASE + NRF51_NVMC_CONFIG, 0x01);
222     for (i = 0; i < FLASH_SIZE / 4; i++) {
223         qtest_writel(qts, NRF51_FLASH_BASE + i * 4, i);
224         g_assert_cmpuint(qtest_readl(qts, NRF51_FLASH_BASE + i * 4), ==, i);
225     }
226     qtest_writel(qts, NRF51_NVMC_BASE + NRF51_NVMC_CONFIG, 0x00);
227 
228     qtest_writel(qts, NRF51_NVMC_BASE + NRF51_NVMC_CONFIG, 0x02);
229     qtest_writel(qts, NRF51_NVMC_BASE + NRF51_NVMC_ERASEALL, 0x01);
230     qtest_writel(qts, NRF51_NVMC_BASE + NRF51_NVMC_CONFIG, 0x00);
231 
232     for (i = 0; i < FLASH_SIZE / 4; i++) {
233         g_assert_cmpuint(qtest_readl(qts, NRF51_FLASH_BASE + i * 4),
234                          ==, 0xFFFFFFFF);
235     }
236 
237     /* Erase UICR */
238     qtest_writel(qts, NRF51_NVMC_BASE + NRF51_NVMC_CONFIG, 0x02);
239     qtest_writel(qts, NRF51_NVMC_BASE + NRF51_NVMC_ERASEUICR, 0x01);
240     qtest_writel(qts, NRF51_NVMC_BASE + NRF51_NVMC_CONFIG, 0x00);
241 
242     for (i = 0; i < NRF51_UICR_SIZE / 4; i++) {
243         g_assert_cmpuint(qtest_readl(qts, NRF51_UICR_BASE + i * 4),
244                          ==, 0xFFFFFFFF);
245     }
246 
247     qtest_writel(qts, NRF51_NVMC_BASE + NRF51_NVMC_CONFIG, 0x01);
248     for (i = 0; i < NRF51_UICR_SIZE / 4; i++) {
249         qtest_writel(qts, NRF51_UICR_BASE + i * 4, i);
250         g_assert_cmpuint(qtest_readl(qts, NRF51_UICR_BASE + i * 4), ==, i);
251     }
252     qtest_writel(qts, NRF51_NVMC_BASE + NRF51_NVMC_CONFIG, 0x00);
253 
254     qtest_writel(qts, NRF51_NVMC_BASE + NRF51_NVMC_CONFIG, 0x02);
255     qtest_writel(qts, NRF51_NVMC_BASE + NRF51_NVMC_ERASEUICR, 0x01);
256     qtest_writel(qts, NRF51_NVMC_BASE + NRF51_NVMC_CONFIG, 0x00);
257 
258     for (i = 0; i < NRF51_UICR_SIZE / 4; i++) {
259         g_assert_cmpuint(qtest_readl(qts, NRF51_UICR_BASE + i * 4),
260                          ==, 0xFFFFFFFF);
261     }
262 
263     qtest_quit(qts);
264 }
265 
266 static void test_nrf51_gpio(void)
267 {
268     size_t i;
269     uint32_t actual, expected;
270 
271     struct {
272         hwaddr addr;
273         uint32_t expected;
274     } const reset_state[] = {
275         {NRF51_GPIO_REG_OUT, 0x00000000}, {NRF51_GPIO_REG_OUTSET, 0x00000000},
276         {NRF51_GPIO_REG_OUTCLR, 0x00000000}, {NRF51_GPIO_REG_IN, 0x00000000},
277         {NRF51_GPIO_REG_DIR, 0x00000000}, {NRF51_GPIO_REG_DIRSET, 0x00000000},
278         {NRF51_GPIO_REG_DIRCLR, 0x00000000}
279     };
280 
281     QTestState *qts = qtest_init("-M microbit");
282 
283     /* Check reset state */
284     for (i = 0; i < ARRAY_SIZE(reset_state); i++) {
285         expected = reset_state[i].expected;
286         actual = qtest_readl(qts, NRF51_GPIO_BASE + reset_state[i].addr);
287         g_assert_cmpuint(actual, ==, expected);
288     }
289 
290     for (i = 0; i < NRF51_GPIO_PINS; i++) {
291         expected = 0x00000002;
292         actual = qtest_readl(qts, NRF51_GPIO_BASE +
293                                   NRF51_GPIO_REG_CNF_START + i * 4);
294         g_assert_cmpuint(actual, ==, expected);
295     }
296 
297     /* Check dir bit consistency between dir and cnf */
298     /* Check set via DIRSET */
299     expected = 0x80000001;
300     qtest_writel(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_DIRSET, expected);
301     actual = qtest_readl(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_DIR);
302     g_assert_cmpuint(actual, ==, expected);
303     actual = qtest_readl(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_CNF_START)
304              & 0x01;
305     g_assert_cmpuint(actual, ==, 0x01);
306     actual = qtest_readl(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_CNF_END) & 0x01;
307     g_assert_cmpuint(actual, ==, 0x01);
308 
309     /* Check clear via DIRCLR */
310     qtest_writel(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_DIRCLR, 0x80000001);
311     actual = qtest_readl(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_DIR);
312     g_assert_cmpuint(actual, ==, 0x00000000);
313     actual = qtest_readl(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_CNF_START)
314              & 0x01;
315     g_assert_cmpuint(actual, ==, 0x00);
316     actual = qtest_readl(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_CNF_END) & 0x01;
317     g_assert_cmpuint(actual, ==, 0x00);
318 
319     /* Check set via DIR */
320     expected = 0x80000001;
321     qtest_writel(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_DIR, expected);
322     actual = qtest_readl(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_DIR);
323     g_assert_cmpuint(actual, ==, expected);
324     actual = qtest_readl(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_CNF_START)
325              & 0x01;
326     g_assert_cmpuint(actual, ==, 0x01);
327     actual = qtest_readl(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_CNF_END) & 0x01;
328     g_assert_cmpuint(actual, ==, 0x01);
329 
330     /* Reset DIR */
331     qtest_writel(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_DIR, 0x00000000);
332 
333     /* Check Input propagates */
334     qtest_writel(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_CNF_START, 0x00);
335     qtest_set_irq_in(qts, "/machine/nrf51", "unnamed-gpio-in", 0, 0);
336     actual = qtest_readl(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_IN) & 0x01;
337     g_assert_cmpuint(actual, ==, 0x00);
338     qtest_set_irq_in(qts, "/machine/nrf51", "unnamed-gpio-in", 0, 1);
339     actual = qtest_readl(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_IN) & 0x01;
340     g_assert_cmpuint(actual, ==, 0x01);
341     qtest_set_irq_in(qts, "/machine/nrf51", "unnamed-gpio-in", 0, -1);
342     actual = qtest_readl(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_IN) & 0x01;
343     g_assert_cmpuint(actual, ==, 0x01);
344     qtest_writel(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_CNF_START, 0x02);
345 
346     /* Check pull-up working */
347     qtest_set_irq_in(qts, "/machine/nrf51", "unnamed-gpio-in", 0, 0);
348     qtest_writel(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_CNF_START, 0b0000);
349     actual = qtest_readl(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_IN) & 0x01;
350     g_assert_cmpuint(actual, ==, 0x00);
351     qtest_writel(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_CNF_START, 0b1110);
352     actual = qtest_readl(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_IN) & 0x01;
353     g_assert_cmpuint(actual, ==, 0x01);
354     qtest_writel(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_CNF_START, 0x02);
355 
356     /* Check pull-down working */
357     qtest_set_irq_in(qts, "/machine/nrf51", "unnamed-gpio-in", 0, 1);
358     qtest_writel(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_CNF_START, 0b0000);
359     actual = qtest_readl(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_IN) & 0x01;
360     g_assert_cmpuint(actual, ==, 0x01);
361     qtest_writel(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_CNF_START, 0b0110);
362     actual = qtest_readl(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_IN) & 0x01;
363     g_assert_cmpuint(actual, ==, 0x00);
364     qtest_writel(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_CNF_START, 0x02);
365     qtest_set_irq_in(qts, "/machine/nrf51", "unnamed-gpio-in", 0, -1);
366 
367     /* Check Output propagates */
368     qtest_irq_intercept_out(qts, "/machine/nrf51");
369     qtest_writel(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_CNF_START, 0b0011);
370     qtest_writel(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_OUTSET, 0x01);
371     g_assert_true(qtest_get_irq(qts, 0));
372     qtest_writel(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_OUTCLR, 0x01);
373     g_assert_false(qtest_get_irq(qts, 0));
374 
375     /* Check self-stimulation */
376     qtest_writel(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_CNF_START, 0b01);
377     qtest_writel(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_OUTSET, 0x01);
378     actual = qtest_readl(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_IN) & 0x01;
379     g_assert_cmpuint(actual, ==, 0x01);
380 
381     qtest_writel(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_OUTCLR, 0x01);
382     actual = qtest_readl(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_IN) & 0x01;
383     g_assert_cmpuint(actual, ==, 0x00);
384 
385     /*
386      * Check short-circuit - generates an guest_error which must be checked
387      * manually as long as qtest can not scan qemu_log messages
388      */
389     qtest_writel(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_CNF_START, 0b01);
390     qtest_writel(qts, NRF51_GPIO_BASE + NRF51_GPIO_REG_OUTSET, 0x01);
391     qtest_set_irq_in(qts, "/machine/nrf51", "unnamed-gpio-in", 0, 0);
392 
393     qtest_quit(qts);
394 }
395 
396 static void timer_task(QTestState *qts, hwaddr task)
397 {
398     qtest_writel(qts, NRF51_TIMER_BASE + task, NRF51_TRIGGER_TASK);
399 }
400 
401 static void timer_clear_event(QTestState *qts, hwaddr event)
402 {
403     qtest_writel(qts, NRF51_TIMER_BASE + event, NRF51_EVENT_CLEAR);
404 }
405 
406 static void timer_set_bitmode(QTestState *qts, uint8_t mode)
407 {
408     qtest_writel(qts, NRF51_TIMER_BASE + NRF51_TIMER_REG_BITMODE, mode);
409 }
410 
411 static void timer_set_prescaler(QTestState *qts, uint8_t prescaler)
412 {
413     qtest_writel(qts, NRF51_TIMER_BASE + NRF51_TIMER_REG_PRESCALER, prescaler);
414 }
415 
416 static void timer_set_cc(QTestState *qts, size_t idx, uint32_t value)
417 {
418     qtest_writel(qts, NRF51_TIMER_BASE + NRF51_TIMER_REG_CC0 + idx * 4, value);
419 }
420 
421 static void timer_assert_events(QTestState *qts, uint32_t ev0, uint32_t ev1,
422                                 uint32_t ev2, uint32_t ev3)
423 {
424     g_assert(qtest_readl(qts, NRF51_TIMER_BASE + NRF51_TIMER_EVENT_COMPARE_0)
425              == ev0);
426     g_assert(qtest_readl(qts, NRF51_TIMER_BASE + NRF51_TIMER_EVENT_COMPARE_1)
427              == ev1);
428     g_assert(qtest_readl(qts, NRF51_TIMER_BASE + NRF51_TIMER_EVENT_COMPARE_2)
429              == ev2);
430     g_assert(qtest_readl(qts, NRF51_TIMER_BASE + NRF51_TIMER_EVENT_COMPARE_3)
431              == ev3);
432 }
433 
434 static void test_nrf51_timer(void)
435 {
436     uint32_t steps_to_overflow = 408;
437     QTestState *qts = qtest_init("-M microbit");
438 
439     /* Compare Match */
440     timer_task(qts, NRF51_TIMER_TASK_STOP);
441     timer_task(qts, NRF51_TIMER_TASK_CLEAR);
442 
443     timer_clear_event(qts, NRF51_TIMER_EVENT_COMPARE_0);
444     timer_clear_event(qts, NRF51_TIMER_EVENT_COMPARE_1);
445     timer_clear_event(qts, NRF51_TIMER_EVENT_COMPARE_2);
446     timer_clear_event(qts, NRF51_TIMER_EVENT_COMPARE_3);
447 
448     timer_set_bitmode(qts, NRF51_TIMER_WIDTH_16); /* 16 MHz Timer */
449     timer_set_prescaler(qts, 0);
450     /* Swept over in first step */
451     timer_set_cc(qts, 0, 2);
452     /* Barely miss on first step */
453     timer_set_cc(qts, 1, 162);
454     /* Spot on on third step */
455     timer_set_cc(qts, 2, 480);
456 
457     timer_assert_events(qts, 0, 0, 0, 0);
458 
459     timer_task(qts, NRF51_TIMER_TASK_START);
460     qtest_clock_step(qts, 10000);
461     timer_assert_events(qts, 1, 0, 0, 0);
462 
463     /* Swept over on first overflow */
464     timer_set_cc(qts, 3, 114);
465 
466     qtest_clock_step(qts, 10000);
467     timer_assert_events(qts, 1, 1, 0, 0);
468 
469     qtest_clock_step(qts, 10000);
470     timer_assert_events(qts, 1, 1, 1, 0);
471 
472     /* Wrap time until internal counter overflows */
473     while (steps_to_overflow--) {
474         timer_assert_events(qts, 1, 1, 1, 0);
475         qtest_clock_step(qts, 10000);
476     }
477 
478     timer_assert_events(qts, 1, 1, 1, 1);
479 
480     timer_clear_event(qts, NRF51_TIMER_EVENT_COMPARE_0);
481     timer_clear_event(qts, NRF51_TIMER_EVENT_COMPARE_1);
482     timer_clear_event(qts, NRF51_TIMER_EVENT_COMPARE_2);
483     timer_clear_event(qts, NRF51_TIMER_EVENT_COMPARE_3);
484     timer_assert_events(qts, 0, 0, 0, 0);
485 
486     timer_task(qts, NRF51_TIMER_TASK_STOP);
487 
488     /* Test Proposal: Stop/Shutdown */
489     /* Test Proposal: Shortcut Compare -> Clear */
490     /* Test Proposal: Shortcut Compare -> Stop */
491     /* Test Proposal: Counter Mode */
492 
493     qtest_quit(qts);
494 }
495 
496 int main(int argc, char **argv)
497 {
498     g_test_init(&argc, &argv, NULL);
499 
500     qtest_add_func("/microbit/nrf51/uart", test_nrf51_uart);
501     qtest_add_func("/microbit/nrf51/gpio", test_nrf51_gpio);
502     qtest_add_func("/microbit/nrf51/nvmc", test_nrf51_nvmc);
503     qtest_add_func("/microbit/nrf51/timer", test_nrf51_timer);
504     qtest_add_func("/microbit/microbit/i2c", test_microbit_i2c);
505 
506     return g_test_run();
507 }
508