HD44780 connected over RP2040 (RPi Pico)

General Discussion
3

Here now the patch for using the LCD2004A with an TXS0108E on the RPi Pico:

diff --git a/src/lcd_hd44780.c b/src/lcd_hd44780.c
index 0afca915..bd142d58 100644
--- a/src/lcd_hd44780.c
+++ b/src/lcd_hd44780.c
@@ -45,7 +45,6 @@ static __always_inline void
 hd44780_xmit_bits(uint8_t toggle, struct gpio_out e, struct gpio_out d4
                   , struct gpio_out d5, struct gpio_out d6, struct gpio_out d7)
 {
-    gpio_out_toggle(e);
     if (toggle & 0x10)
         gpio_out_toggle(d4);
     if (toggle & 0x20)
@@ -54,8 +53,14 @@ hd44780_xmit_bits(uint8_t toggle, struct gpio_out e, struct gpio_out d4
         gpio_out_toggle(d6);
     if (toggle & 0x80)
         gpio_out_toggle(d7);
-    ndelay(230);
-    gpio_out_toggle(e);
+    
+    const uint32_t delay = 12000;
+    
+    ndelay(delay);
+    gpio_out_write(e, 0);
+    ndelay(delay);
+    gpio_out_write(e, 1);
+    ndelay(delay);
 }
 
 // Transmit 8 bits to the chip
@@ -94,7 +99,7 @@ command_config_hd44780(uint32_t *args)
 {
     struct hd44780 *h = oid_alloc(args[0], command_config_hd44780, sizeof(*h));
     h->rs = gpio_out_setup(args[1], 0);
-    h->e = gpio_out_setup(args[2], 0);
+    h->e = gpio_out_setup(args[2], 1);
     h->d4 = gpio_out_setup(args[3], 0);
     h->d5 = gpio_out_setup(args[4], 0);
     h->d6 = gpio_out_setup(args[5], 0);
@@ -126,6 +131,7 @@ command_hd44780_send_cmds(uint32_t *args)
     gpio_out_write(h->rs, 0);
     uint8_t len = args[1], *cmds = command_decode_ptr(args[2]);
     hd44780_xmit(h, len, cmds);
+    ndelay(3000);
 }
 DECL_COMMAND(command_hd44780_send_cmds, "hd44780_send_cmds oid=%c cmds=%*s");
 
@@ -136,6 +142,7 @@ command_hd44780_send_data(uint32_t *args)
     gpio_out_write(h->rs, 1);
     uint8_t len = args[1], *data = command_decode_ptr(args[2]);
     hd44780_xmit(h, len, data);
+    ndelay(3000);
 }
 DECL_COMMAND(command_hd44780_send_data, "hd44780_send_data oid=%c data=%*s");

For the next I’ll try to it completly on 3.3V and if it works, i’ll report back.