📝 7 Jan 2024
+📝 7 Jan 2024
Happy New Year! 2024 is here and we’re running Apache NuttX RTOS (Real-Time Operating System) on Single-Board Computers with plenty of RAM…
Like Pine64 Ox64 BL808 RISC-V SBC with 64 MB RAM! (Pic below)
@@ -409,7 +408,10 @@ Hint: used config file '/workspaces/bookworm/apps/config.nims' [Conf] .................................................................................................................................... Hint: mm: orc; opt: size; options: -d:danger 92931 lines; 1.214s; 137.633MiB peakmem; proj: /workspaces/bookworm/apps/examples/hello_nim/hello_nim_async.nim; out: /workspaces/bookworm/apps/.nimcache/hello_nim_async.json [SuccessX] -
GPIO 29 in BL808 Reference Manual (Page 119)
+Our Nim Experiment needs an LED Driver for Ox64…
What’s the Quickest Way to create a NuttX LED Driver?
U-Boot Bootloader can help! Power up Ox64 and press Enter a few times to reveal the U-Boot Command Prompt.
@@ -450,48 +452,47 @@ $ md 0x20000938 1How did we figure out the Magic Bits for GPIO 29?
-TODO
-From BL808 Reference Manual Page 56, “Normal GPIO Output Mode”…
+From BL808 Reference Manual Page 56, “Normal GPIO Output Mode”…
Set reg_gpio_xx_oe (Bit 6) to 1 to enable the GPIO output mode
+
Set reg_gpio_29_oe (Bit 6) to 1 to enable GPIO Output Mode
= (1 << 6)
Set reg_gpio_xx_func_sel (Bits 8 to 12) to 11 to enter the SWGPIO mode
+
Set reg_gpio_29_func_sel (Bits 8 to 12) to 11 to enter SWGPIO Mode
= (11 << 8)
Set reg_gpio_xx_mode (Bits 30 to 31) to 0 to enable the normal output function of I/O
+
Set reg_gpio_29_mode (Bits 30 to 31) to 0 to enable Normal Output Function of I/O
= (0 << 30)
Set reg_gpio_xx_pu (Bit 4) and reg_gpio_xx_pd (Bit 5) to 0 to disable the internal pull-up and pull-down functions
+
Set reg_gpio_29_pu (Bit 4) and reg_gpio_29_pd (Bit 5) to 0 to disable Internal Pull-Up and Pull-Down functions
= (0 << 4)
Set the level of I/O pin through reg_gpio_xx_o (Bit 24)
+
Set the Pin Level (0 or 1) through reg_gpio_29_o (Bit 24)
= Either (0 << 24) Or (1 << 24)
TODO: (GPIO Bits are listed in the pic above)
+(GPIO Bits are listed in the pic above)
Which means…
Set GPIO Output to 0
+
Set GPIO Output to 0
= (1 << 6) | (11 << 8) | (0 << 30) | (0 << 4) | (0 << 24)
-= 0xb40
0xB40
Set GPIO Output to 1
+
Set GPIO Output to 1
= (1 << 6) | (11 << 8) | (0 << 30) | (0 << 4) | (1 << 24)
-= 0x1000b40
0x100 0B40
TODO
-How to flip the GPIO in our NuttX LED Driver?
-This is how we flip the GPIO in our NuttX LED Driver: bl808_userleds.c
-// Switch the LEDs On and Off according to the LED Set
+And we write the above values to GPIO 29 Register at 0x2000 0938 (gpio_cfg29)
+How to flip the GPIO in our LED Driver?
+We do this in our NuttX LED Driver: bl808_userleds.c
+// Flip the LEDs On and Off according to the LED Set
// (Bit 0 = LED 0)
void board_userled_all(uint32_t ledset) {
@@ -504,16 +505,16 @@ void board_userled_all(uint32_t ledset) {
// If this is LED 0...
if (i == 0) {
- // Switch it On or Off?
+ // Flip it On or Off?
if (val) {
- // Switch LED 0 (GPIO 29) to On:
+ // Flip LED 0 (GPIO 29) to On:
// Set gpio_cfg29 to (1 << 6) | (11 << 8) | (0 << 30) | (0 << 4) | (1 << 24)
// mw 0x20000938 0x1000b40 1
*(volatile uint32_t *) 0x20000938 = 0x1000b40;
} else {
- // Switch LED 0 (GPIO 29) to Off:
+ // Flip LED 0 (GPIO 29) to Off:
// Set gpio_cfg29 to (1 << 6) | (11 << 8) | (0 << 30) | (0 << 4) | (0 << 24)
// mw 0x20000938 0xb40 1
*(volatile uint32_t *) 0x20000938 = 0xb40;
@@ -1148,198 +1149,7 @@ void up_timer_initialize(void) {
Now the sleep command works correctly in NuttX Shell!
Here’s the log (ignore the errors)
-16 LED Driver for Ox64 BL808
-TODO
-We wish to blink an LED with Nim on Ox64…
-
-But first we need a barebones NuttX LED Driver for Ox64.
-How to create the NuttX LED Driver?
-We assume LED is connected to GPIO 29, Pin 21. (See the Pinout)
-(With a 47 Ohm Resistor, yellow-purple-black-gold)
-How do we flip a BL808 GPIO High and Low?
-From BL808 Reference Manual Page 56, “Normal GPIO Output Mode”…
-
--
-
Set reg_gpio_xx_oe (Bit 6) to 1 to enable the GPIO output mode
-= (1 << 6)
-
--
-
Set reg_gpio_xx_func_sel (Bits 8 to 12) to 11 to enter the SWGPIO mode
-= (11 << 8)
-
--
-
Set reg_gpio_xx_mode (Bits 30 to 31) to 0 to enable the normal output function of I/O
-= (0 << 30)
-
--
-
Set reg_gpio_xx_pu (Bit 4) and reg_gpio_xx_pd (Bit 5) to 0 to disable the internal pull-up and pull-down functions
-= (0 << 4)
-
--
-
Set the level of I/O pin through reg_gpio_xx_o (Bit 24)
-= Either (0 << 24) Or (1 << 24)
-
-
-(GPIO Bit Definitions are below)
-Which means…
-
--
-
Set GPIO Output to 0
-= (1 << 6) | (11 << 8) | (0 << 30) | (0 << 4) | (0 << 24)
-= 0xb40
-
--
-
Set GPIO Output to 1
-= (1 << 6) | (11 << 8) | (0 << 30) | (0 << 4) | (1 << 24)
-= 0x1000b40
-
-
-How to test this?
-GPIO 29 Base Address gpio_cfg29 is 0x20000938.
-For testing, we run U-Boot Bootloader Commands to set GPIO 29 to High and Low…
-## Dump gpio_cfg29 at 0x20000938
-$ md 0x20000938 1
-20000938: 00400803 ..@.
-
-## Set GPIO Output to 0: (1 << 6) | (11 << 8) | (0 << 30) | (0 << 4) | (0 << 24)
-## = 0xb40
-$ mw 0x20000938 0xb40 1
-$ md 0x20000938 1
-20000938: 00000b40 @...
-
-## Set GPIO Output to 1: (1 << 6) | (11 << 8) | (0 << 30) | (0 << 4) | (1 << 24)
-## = 0x1000b40
-$ mw 0x20000938 0x1000b40 1
-$ md 020000938 1
-20000938: 01000b40 @...
-
-And U-Boot switches the LED On and Off correctly yay!
-How to flip the GPIO in our NuttX LED Driver?
-This is how we flip the GPIO in our NuttX LED Driver: bl808_userleds.c
-// Switch the LEDs On and Off according to the LED Set
-// (Bit 0 = LED 0)
-void board_userled_all(uint32_t ledset)
-{
- _info("ledset=0x%x\n", ledset);////
- int i;
-
- // For LED 0 to 2...
- for (i = 0; i < BOARD_LEDS; i++)
- {
- // Get the desired state of the LED
- bool val = ((ledset & g_led_setmap[i]) != 0);
- _info("led=%d, val=%d\n", i, val);////
-
- // If this is LED 0...
- if (i == 0)
- {
- // Switch it On or Off?
- if (val)
- {
- // Switch LED 0 (GPIO 29) to On:
- // Set gpio_cfg29 to (1 << 6) | (11 << 8) | (0 << 30) | (0 << 4) | (1 << 24)
- // mw 0x20000938 0x1000b40 1
- *(volatile uint32_t *) 0x20000938 = 0x1000b40;
- }
- else
- {
- // Switch LED 0 (GPIO 29) to Off:
- // Set gpio_cfg29 to (1 << 6) | (11 << 8) | (0 << 30) | (0 << 4) | (0 << 24)
- // mw 0x20000938 0xb40 1
- *(volatile uint32_t *) 0x20000938 = 0xb40;
- }
- }
- ////TODO: a64_pio_write(g_led_map[i], (ledset & g_led_setmap[i]) != 0);
- }
-}
-
-And our LED Driver works OK with Nim: It blinks our LED on Ox64 BL808 SBC!
-
--
-
-
--
-
-
--
-
-
-
-Later we’ll replace the (awful) code above by the BL808 GPIO Driver. Which we’ll copy from NuttX for BL602.
-How did we get the GPIO Bit Definitions?
-From BL808 Reference Manual Page 119…
-4.8.30 gpio_cfg29
-Base Address：0x20000938
-
-Bits Name Type Reset Description
-
-31:30 reg_gpio_29_mode r/w 0 When GPIO Function Selected to SWGPIO
-00 (Output Value Mode): GPIO Output by reg_gpio_x_o
-Value
-01 (Set/Celar Mode ) :GPIO Output set by reg_gpio_x_set
-and clear by reg_gpio_x_clr
-10 : SWGPIO Source comes from GPIO DMA (GPIO DMA
-Mode), GPIO Output value by gpio_dma_o
-11: SWGPIO Source comes from GPIO DMA (GPIO DMA
-Mode), GPIO Outout value by gpio_dma_set/gpio_dma_clr
-
-29 RSVD
-
-28 reg_gpio_29_i r 0
-
-27 RSVD
-
-26 reg_gpio_29_clr w1p 0 When SWGPIO @ Set/Clear Mode
-Set this bit will clear GPIO output value to 0,when set/clr at
-the same time, only set take effect
-
-25 reg_gpio_29_set w1p 0 When SWGPIO @ Set/Clear Mode
-Set this bit will set GPIO output value to 1,when set/clr at
-the same time, only set take effect
-
-24 reg_gpio_29_o r/w 0 When SWGPIO @ Output Value Mode
-00 : GPIO Value changes according to this value
-01 : GPIO Value Set by this register and clr by clr_reg
-
-23 RSVD
-
-22 reg_gpio_29_int_mask r/w 1 mask interrupt (1)
-
-21 gpio_29_int_stat r 0 interrupt status
-
-20 reg_gpio_29_int_clr r/w 0 clear interrupt
-
-19:16 reg_gpio_29_int_mode_set r/w 0 0000 : sync falling edge trigger
-0001 : sync rising edge trigger
-0010 : sync low level trigger
-0011 : sync high level trigger
-01xx : sync rising & falling edge trigger
-1000 : async falling edge trigger
-1001 : async rising edge trigger
-1010 : async low level trigger
-1011 : async high level trigger
-
-15:13 RSVD
-
-12:8 reg_gpio_29_func_sel r/w 5’hB GPIO Function Select (Default : SW-GPIO)
-
-7 RSVD
-
-6 reg_gpio_29_oe r/w 0 Register Controlled GPIO Output Enable (Used when GPIO
-Function select to Register Control GPIO)
-
-5 reg_gpio_29_pd r/w 0 GPIO Pull Down Control
-
-4 reg_gpio_29_pu r/w 0 GPIO Pull Up Control
-
-3:2 reg_gpio_29_drv r/w 0 GPIO Driving Control
-
-1 reg_gpio_29_smt r/w 1 GPIO SMT Control
-
-0 reg_gpio_29_ie r/w 0 GPIO Input Enable
-
17 What’s Next
+16 What’s Next
TODO
Many Thanks to my GitHub Sponsors (and the awesome NuttX Community) for supporting my work! This article wouldn’t have been possible without your support.
@@ -1364,9 +1174,9 @@ Function select to Register Control GPIO)
Got a question, comment or suggestion? Create an Issue or submit a Pull Request here…
-18 Appendix: Build NuttX for QEMU
+17 Appendix: Build NuttX for QEMU
TODO
-19 Appendix: Build NuttX for Ox64
+18 Appendix: Build NuttX for Ox64
TODO: ox64-1
