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RISCY BUSINESS»Episode Guide
Getting the PWM Interrupts to Fire
References ▼
Crowd Supply
HiFive Unleashed
[1]0:07[2]5:28
SiFive Developers
HiFive1 Getting Started Guide
[3]25:12
SiFive Developers
Freedom E300 Platform Reference Manual
[4]55:40
The Ganssle Group
A Guide to Debouncing, or, How to Debounce a Contact in Two Easy Pages
[5]1:05:02
Gumroad
RISCY BUSINESS
[6]1:15:44
Patreon
miotatsu is creating RISCY BUSINESS
[7]1:15:44
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0:07Plug SiFive's Linux-capable HiFive Unleashed chip1
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0:07Plug SiFive's Linux-capable HiFive Unleashed chip1
📖
0:07Plug SiFive's Linux-capable HiFive Unleashed chip1
📖
5:28Check out the HiFive Unleashed specs2 with exciting thoughts for it in RISCY BUSINESS
📖
5:28Check out the HiFive Unleashed specs2 with exciting thoughts for it in RISCY BUSINESS
📖
5:28Check out the HiFive Unleashed specs2 with exciting thoughts for it in RISCY BUSINESS
📖
16:04Plan to port pcalc to RISC-V to work on the HiFive Unleashed
🗩
16:04Plan to port pcalc to RISC-V to work on the HiFive Unleashed
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16:04Plan to port pcalc to RISC-V to work on the HiFive Unleashed
🗩
21:35Determine to continue our investigation into the trap on mstatus in pwm_speed_test.c and to run it in gdb
🗩
21:35Determine to continue our investigation into the trap on mstatus in pwm_speed_test.c and to run it in gdb
🗩
21:35Determine to continue our investigation into the trap on mstatus in pwm_speed_test.c and to run it in gdb
🗩
25:12Read section 6.2.4 - Debugging Running Programs3
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25:12Read section 6.2.4 - Debugging Running Programs3
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25:12Read section 6.2.4 - Debugging Running Programs3
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27:33Comment out the set_csr(mie, MIP_MTIP) and set_csr(mstatus, MSTATUS_MIE) calls in main()
27:33Comment out the set_csr(mie, MIP_MTIP) and set_csr(mstatus, MSTATUS_MIE) calls in main()
27:33Comment out the set_csr(mie, MIP_MTIP) and set_csr(mstatus, MSTATUS_MIE) calls in main()
28:06Make and upload pwm_speed_test
28:06Make and upload pwm_speed_test
28:06Make and upload pwm_speed_test
29:49Reset the board, to see that we don't trap
🏃
29:49Reset the board, to see that we don't trap
🏃
29:49Reset the board, to see that we don't trap
🏃
29:56Uncomment the set_csr(mstatus, MSTATUS_MIE) call in main()
29:56Uncomment the set_csr(mstatus, MSTATUS_MIE) call in main()
29:56Uncomment the set_csr(mstatus, MSTATUS_MIE) call in main()
30:08Make, upload and reset to find that we unexpectedly fail to trap
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30:08Make, upload and reset to find that we unexpectedly fail to trap
🏃
30:08Make, upload and reset to find that we unexpectedly fail to trap
🏃
31:15Reset the board in safe mode, and find that we still fail to trap
🏃
31:15Reset the board in safe mode, and find that we still fail to trap
🏃
31:15Reset the board in safe mode, and find that we still fail to trap
🏃
32:41Uncomment the handle_m_time_interrupt() and set_csr(mie. MIP_MTIP) calls in main()
32:41Uncomment the handle_m_time_interrupt() and set_csr(mie. MIP_MTIP) calls in main()
32:41Uncomment the handle_m_time_interrupt() and set_csr(mie. MIP_MTIP) calls in main()
33:10Run to find that we trap after a short delay
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33:10Run to find that we trap after a short delay
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33:10Run to find that we trap after a short delay
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33:46Read carefully through handle_m_time_interrupt()
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33:46Read carefully through handle_m_time_interrupt()
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33:46Read carefully through handle_m_time_interrupt()
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36:29Copy the busy loop from led_fade.c into uart_init() in init.c, and reduce the wait time in handle_m_time_interrupt() to 2 seconds
36:29Copy the busy loop from led_fade.c into uart_init() in init.c, and reduce the wait time in handle_m_time_interrupt() to 2 seconds
36:29Copy the busy loop from led_fade.c into uart_init() in init.c, and reduce the wait time in handle_m_time_interrupt() to 2 seconds
38:11Run the program to find that we trap after waiting 2 seconds
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38:11Run the program to find that we trap after waiting 2 seconds
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38:11Run the program to find that we trap after waiting 2 seconds
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38:54Discover the USE_M_TIME #ifdef in init.c and check out the Makefile of other demos that call handle_m_time_interrupt() to find that they contain the flag -DUSE_M_TIME
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38:54Discover the USE_M_TIME #ifdef in init.c and check out the Makefile of other demos that call handle_m_time_interrupt() to find that they contain the flag -DUSE_M_TIME
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38:54Discover the USE_M_TIME #ifdef in init.c and check out the Makefile of other demos that call handle_m_time_interrupt() to find that they contain the flag -DUSE_M_TIME
📖
40:35Add -DUSE_PLIC and -DUSE_M_TIME to the pwm_speed_test Makefile
40:35Add -DUSE_PLIC and -DUSE_M_TIME to the pwm_speed_test Makefile
40:35Add -DUSE_PLIC and -DUSE_M_TIME to the pwm_speed_test Makefile
42:00Run the program to find that it now works beautifully
🏃
42:00Run the program to find that it now works beautifully
🏃
42:00Run the program to find that it now works beautifully
🏃
42:20Delete all the timer interrupt code, in favour of the PLIC code
42:20Delete all the timer interrupt code, in favour of the PLIC code
42:20Delete all the timer interrupt code, in favour of the PLIC code
46:59Run the program to see "Hello, World" but no interrupt or trap
🏃
46:59Run the program to see "Hello, World" but no interrupt or trap
🏃
46:59Run the program to see "Hello, World" but no interrupt or trap
🏃
48:47Compare our PLIC code with that in global_interrupts.c, try to change PWM0_REG(PWM_CMP0) to PWM0_REG(PWM_COUNT), and instead uncomment the PLIC_set_priority() call in main()
48:47Compare our PLIC code with that in global_interrupts.c, try to change PWM0_REG(PWM_CMP0) to PWM0_REG(PWM_COUNT), and instead uncomment the PLIC_set_priority() call in main()
48:47Compare our PLIC code with that in global_interrupts.c, try to change PWM0_REG(PWM_CMP0) to PWM0_REG(PWM_COUNT), and instead uncomment the PLIC_set_priority() call in main()
53:15Run the program and hit our PWM interrupt!
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53:15Run the program and hit our PWM interrupt!
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53:15Run the program and hit our PWM interrupt!
🏃
53:44Determine to go back to timing
🗩
53:44Determine to go back to timing
🗩
53:44Determine to go back to timing
🗩
55:40Read Chapter 15 - E300 Pulse-Width Modulation (PWM) Peripheral4
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55:40Read Chapter 15 - E300 Pulse-Width Modulation (PWM) Peripheral4
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55:40Read Chapter 15 - E300 Pulse-Width Modulation (PWM) Peripheral4
📖
56:42Try setting PWM0_REG(PWM_CMP0) = 0xFFFF
56:42Try setting PWM0_REG(PWM_CMP0) = 0xFFFF
56:42Try setting PWM0_REG(PWM_CMP0) = 0xFFFF
57:30Run the program to see that our interrupts fire pretty fast
🏃
57:30Run the program to see that our interrupts fire pretty fast
🏃
57:30Run the program to see that our interrupts fire pretty fast
🏃
57:51Try to add 0x1 to the timer rearming call
57:51Try to add 0x1 to the timer rearming call
57:51Try to add 0x1 to the timer rearming call
58:11Run the program to see that our interrupts still fire pretty fast
🏃
58:11Run the program to see that our interrupts still fire pretty fast
🏃
58:11Run the program to see that our interrupts still fire pretty fast
🏃
58:26Bump straight up to 0x7 in the timer rearming call
58:26Bump straight up to 0x7 in the timer rearming call
58:26Bump straight up to 0x7 in the timer rearming call
58:44Run the program to see that our interrupts still fire pretty fast
🏃
58:44Run the program to see that our interrupts still fire pretty fast
🏃
58:44Run the program to see that our interrupts still fire pretty fast
🏃
1:00:42Note that we wanted to be in one-shot mode, and try making pwm_0_handler() clear the PWM_CFG register
1:00:42Note that we wanted to be in one-shot mode, and try making pwm_0_handler() clear the PWM_CFG register
1:00:42Note that we wanted to be in one-shot mode, and try making pwm_0_handler() clear the PWM_CFG register
1:02:05Run the program to see that we are correctly in one-shot mode
🏃
1:02:05Run the program to see that we are correctly in one-shot mode
🏃
1:02:05Run the program to see that we are correctly in one-shot mode
🏃
1:02:44Rearm the timer in pwm_0_handler()
1:02:44Rearm the timer in pwm_0_handler()
1:02:44Rearm the timer in pwm_0_handler()
1:03:53Run the program to see that the timer gets rearmed each time, and note that it still runs pretty fast
🏃
1:03:53Run the program to see that the timer gets rearmed each time, and note that it still runs pretty fast
🏃
1:03:53Run the program to see that the timer gets rearmed each time, and note that it still runs pretty fast
🏃
1:05:02Consider the main use-case of PWM interrupts being for debouncing, and plug the Guide to Debouncing5
📖
1:05:02Consider the main use-case of PWM interrupts being for debouncing, and plug the Guide to Debouncing5
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1:05:02Consider the main use-case of PWM interrupts being for debouncing, and plug the Guide to Debouncing5
📖
1:11:04Consider alternate ways to handle debouncing, and uses for PWM interrupts
🗩
1:11:04Consider alternate ways to handle debouncing, and uses for PWM interrupts
🗩
1:11:04Consider alternate ways to handle debouncing, and uses for PWM interrupts
🗩
1:14:24Determine that we have a good understanding of global_interrupts, and to start fully learning timing in the next episode
🗩
1:14:24Determine that we have a good understanding of global_interrupts, and to start fully learning timing in the next episode
🗩
1:14:24Determine that we have a good understanding of global_interrupts, and to start fully learning timing in the next episode
🗩
1:15:44Plug the new Gumroad-powered subscription solution6, along with a note that the Transparency Reports alone remain solely available publicly on Patreon7
🗩
1:15:44Plug the new Gumroad-powered subscription solution6, along with a note that the Transparency Reports alone remain solely available publicly on Patreon7
🗩
1:15:44Plug the new Gumroad-powered subscription solution6, along with a note that the Transparency Reports alone remain solely available publicly on Patreon7
🗩