From 37507ecea3277a99e60c7bb077c6cd406bb80ddb Mon Sep 17 00:00:00 2001
From: Nathan Ringo <nathan@remexre.com>
Date: Sat, 5 Oct 2024 13:44:15 -0500
Subject: Start of the CH559 code, adds a NixOS module for udev rules for the
 boards.

Starter code from https://github.com/MatzElectronics/CH559sdccUSBHost
---
 usbkbd/main.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)
 create mode 100644 usbkbd/main.c

(limited to 'usbkbd/main.c')

diff --git a/usbkbd/main.c b/usbkbd/main.c
new file mode 100644
index 0000000..9d5286d
--- /dev/null
+++ b/usbkbd/main.c
@@ -0,0 +1,55 @@
+#include "ch559.h"
+#include <compiler.h>
+#include <stdint.h>
+
+#ifndef FREQ_SYS
+#define FREQ_SYS 12000000 // System frequency is 12MHz
+#endif
+
+static inline void delay() {
+  uint32_t i;
+  for (i = 0; i < (120000UL); i++) {
+  }
+  __asm__("nop");
+}
+
+void initUART0(unsigned long baud, int alt) {
+  unsigned long x;
+  if (alt) {
+    PORT_CFG |= bP0_OC;
+    P0_DIR |= bTXD_;
+    P0_PU |= bTXD_ | bRXD_;
+    PIN_FUNC |= bUART0_PIN_X;
+  }
+
+  SM0 = 0;
+  SM1 = 1;
+  SM2 = 0;
+  REN = 1;
+  // RCLK = 0;
+  // TCLK = 0;
+  PCON |= SMOD;
+  x = (((unsigned long)FREQ_SYS / 8) / baud + 1) / 2;
+
+  TMOD = TMOD & ~bT1_GATE & ~bT1_CT & ~MASK_T1_MOD | bT1_M1;
+  T2MOD = T2MOD | bTMR_CLK | bT1_CLK;
+  TH1 = (256 - x) & 255;
+  TR1 = 1;
+  TI = 1;
+}
+
+void main() {
+  P4_DIR = 0b00001100;
+  P4_OUT = 0b00000100;
+
+  initUART0(9600, 1);
+
+  while (1) {
+    delay();
+    P4_OUT ^= 0b00001100;
+    SBUF = 'Z';
+    while (!TI)
+      ;
+    TI = 1;
+  }
+}
-- 
cgit v1.2.3