From 4a99ede565fa61005f2a6202669adaa87a8ce0ee Mon Sep 17 00:00:00 2001
From: Sam Anthony <sam@samanthony.xyz>
Date: Sat, 16 Aug 2025 12:19:09 -0230
Subject: spi and eeprom modules

---
 sw/spi.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 sw/spi.c

(limited to 'sw/spi.c')

diff --git a/sw/spi.c b/sw/spi.c
new file mode 100644
index 0000000..1793c4d
--- /dev/null
+++ b/sw/spi.c
@@ -0,0 +1,30 @@
+#include <xc.h>
+
+#include <stdint.h>
+
+#include "sys.h"
+#include "types.h"
+
+#include "spi.h"
+
+void
+spiInit(void) {
+	U8 junk;
+
+	TRISBbits.TRISB4 = IN; // SDI
+	TRISCbits.TRISC7 = OUT; // SDO
+	TRISBbits.TRISB6 = OUT; // SCK
+
+	SSPSTAT = 0x00;
+	SSPCON1 = 0x01; // FOSC/16 => 3MHz SPI clock
+	SSPCON1bits.SSPEN = 1; // enable
+	junk = SSPBUF; // dummy read to clear BF
+	(void)junk;
+}
+
+U8
+spiTx(U8 c) {
+	SSPBUF = c;
+	while (!SSPSTATbits.BF) {}
+	return SSPBUF;
+}
-- 
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