Update doc

README.md

@@ -4005,13 +4005,16 @@ And here's the [__RTL Code for C906 MMU__](https://github.com/T-head-Semi/openc9
 
 # Fix the RISC-V Timer with OpenSBI
 
-_The "sleep" command always hangs in NuttX Shell. How to fix it?_
+_The `sleep` command hangs in NuttX Shell. How to fix it?_
 
-That's because we haven't implemented the RISC-V Timer for Ox64! We should call OpenSBI to handle the Timer, [here's the fix](https://github.com/lupyuen2/wip-pinephone-nuttx/commit/57ea5f000636f739ac3cb8ea1e60936798f6c3a9#diff-535879ffd6d9fc8e7d84b37a88bdeb1609c4a90e3777150939a96bed18696aee). (Ignore riscv_mtimer.c, we were verifying that mtime and mtimecmp are unused in Kernel Mode)
+That's because we haven't implemented the RISC-V Timer for Ox64! We should call OpenSBI to handle the Timer, [here's the fix](https://github.com/lupyuen2/wip-pinephone-nuttx/commit/57ea5f000636f739ac3cb8ea1e60936798f6c3a9#diff-535879ffd6d9fc8e7d84b37a88bdeb1609c4a90e3777150939a96bed18696aee).
+
+(Ignore riscv_mtimer.c, we were verifying that mtime and mtimecmp are unused in Kernel Mode)
 
 We only need to change [arch/risc-v/src/bl808/bl808_timerisr.c](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/nim/arch/risc-v/src/bl808/bl808_timerisr.c#L44-L116)
 
 ```c
+// Timer Frequency
 #define MTIMER_FREQ 1000000
 
 // This function is called during start-up to initialize the timer interrupt.
@@ -4023,17 +4026,17 @@ void up_timer_initialize(void) {
 }
 ```
 
-How it works...
+How it works: At startup, `up_timer_initialize` (above) calls...
 
-- [riscv_mtimer_initialize](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/nim/arch/risc-v/src/common/riscv_mtimer.c#L318-L332) calls riscv_mtimer_set_mtimecmp
+- [riscv_mtimer_initialize](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/nim/arch/risc-v/src/common/riscv_mtimer.c#L318-L332) which calls...
 
-- [riscv_mtimer_set_mtimecmp](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/nim/arch/risc-v/src/common/riscv_mtimer.c#L136-L141) calls riscv_sbi_set_timer
+- [riscv_mtimer_set_mtimecmp](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/nim/arch/risc-v/src/common/riscv_mtimer.c#L136-L141) which calls...
 
-- [riscv_sbi_set_timer](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/nim/arch/risc-v/src/common/supervisor/riscv_sbi.c#L94-L107) calls sbi_ecall
+- [riscv_sbi_set_timer](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/nim/arch/risc-v/src/common/supervisor/riscv_sbi.c#L94-L107) which calls...
 
-- [sbi_ecall](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/nim/arch/risc-v/src/common/supervisor/riscv_sbi.c#L53-L76) makes an ecall to OpenSBI
+- [sbi_ecall](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/nim/arch/risc-v/src/common/supervisor/riscv_sbi.c#L53-L76) which makes an ecall to OpenSBI
 
-- Which access the System Timer
+- Which accesses the System Timer
 
 Originally we set MTIMER_FREQ to 10000000: [bl808_timerisr.c](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/nim/arch/risc-v/src/bl808/bl808_timerisr.c#L44-L48)