From 0727556315b67d7eeff9c632f2f576427ae1491d Mon Sep 17 00:00:00 2001
From: Sadeep Madurange <sadeep@asciimx.com>
Date: Thu, 3 Apr 2025 18:00:26 +0800
Subject: Read data  outside of IRQ handler.

---
 nrfm.c | 53 ++++++++++++++++++++++++++++-------------------------
 recv.c | 32 +++++++++++++++++---------------
 2 files changed, 45 insertions(+), 40 deletions(-)

diff --git a/nrfm.c b/nrfm.c
index fb3a0fa..f34eb83 100644
--- a/nrfm.c
+++ b/nrfm.c
@@ -279,37 +279,40 @@ void radio_listen(void)
 
 uint8_t radio_recv(char *buf, uint8_t n)
 {
-	uint8_t rv, readlen, pdlen, maxlen;
+	uint8_t rxdr, readlen, pdlen, maxlen;
 
-	readlen = 0;
 	disable_chip();
 
-	rv = read_reg(0x07);
-	if (rv & ~(1 << 6)) {
-		pdlen = rx_pdlen();	
-		maxlen = pdlen < n ? pdlen : n;
-
-		if (pdlen <= MAXPDLEN) {
-			SPI_PORT &= ~(1 << SPI_SS);
-			SPDR = 0b01100001;
-			while (!(SPSR & (1 << SPIF)))
-				;
-			for (readlen = 0; readlen < maxlen; readlen++) {
-				SPDR = NRF_NOP;
-				while (!(SPSR & (1 << SPIF)))
-					;
-				buf[readlen] = SPDR;
-			}
-			SPI_PORT |= (1 << SPI_SS);
-			if (pdlen != n)
-				flush_rx();
-		} else {
-			flush_rx();
-			readlen = 0;
-		}
+	rxdr = read_reg(0x07) & ~(1 << 6);
+	if (!rxdr) {
+		uart_write_line("DEBUG: RX_DR=0, abort read");
+		return 0;
+	}
 
+	pdlen = rx_pdlen();	
+	if (pdlen > MAXPDLEN) {
+		flush_rx();
 		reset_irqs();
+		uart_write_line("ERROR: PDLEN > MAXPDLEN, abort read");
+		return 0;
 	}
 
+	maxlen = pdlen < n ? pdlen : n;
+	SPI_PORT &= ~(1 << SPI_SS);
+	SPDR = 0b01100001;
+	while (!(SPSR & (1 << SPIF)))
+		;
+	for (readlen = 0; readlen < maxlen; readlen++) {
+		SPDR = NRF_NOP;
+		while (!(SPSR & (1 << SPIF)))
+			;
+		buf[readlen] = SPDR;
+	}
+	SPI_PORT |= (1 << SPI_SS);
+
+	if (pdlen != n)
+		flush_rx();
+	reset_irqs();
+
 	return readlen;
 }
diff --git a/recv.c b/recv.c
index dc5aa44..8321fa8 100644
--- a/recv.c
+++ b/recv.c
@@ -13,8 +13,13 @@
 #define RX_PCMSK       PCMSK2
 #define RX_PCINTVEC    PCINT2_vect
 
+static int rxdr = 0;
+
 int main(void)
 {
+	uint8_t n;
+	char buf[MAXPDLEN + 1];
+
 	uint8_t rxaddr[] = { 194, 178, 83 };
 
 	RX_DDR &= ~(1 << RX_PIN);
@@ -29,25 +34,22 @@ int main(void)
 	sei();
 	radio_listen();
 
-	for (;;)
-		;
+	for (;;) {
+		if (rxdr) {
+			cli();
+			n = radio_recv(buf, MAXPDLEN);
+			buf[n] = '\0';
+			uart_write("INFO: ");
+			uart_write_line(buf);
+			rxdr = 0;
+			sei();
+		}
+	}
 
 	return 0;
 }
 
 ISR(RX_PCINTVEC)
 {
-	uint8_t n;
-	char buf[MAXPDLEN + 1];
-
-	cli();
-
-	uart_write_line("DEBUG: Pin change IRQ");
-
-	n = radio_recv(buf, MAXPDLEN);
-	buf[n] = '\0';
-	uart_write("INFO: ");
-	uart_write_line(buf);
-
-	sei();
+	rxdr = 1;
 }
-- 
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