From c6454367c84a99a4b17b69117f6eb803da610e72 Mon Sep 17 00:00:00 2001
From: Erich Eckner <git@eckner.net>
Date: Mon, 5 Nov 2018 13:39:36 +0100
Subject: multiplexer: wait_tpic_settle_time new

---
 multiplexer.c | 8 ++++++--
 multiplexer.h | 2 ++
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/multiplexer.c b/multiplexer.c
index db1c572..50da183 100644
--- a/multiplexer.c
+++ b/multiplexer.c
@@ -92,14 +92,18 @@ void *put_on_display(void *param)
         break;
       }
       for (column=0; column<8; column++) {
-        GPIO_CLR = 1<<SER_CLK_PIN;
         GPIO_ALTER(column + line == 7) = 1<<SER_DAT_PIN;
+        GPIO_CLR = 1<<SER_CLK_PIN;
+        wait_tpic_settle_time
         GPIO_SET = 1<<SER_CLK_PIN;
+        wait_tpic_settle_time
       }
       for (column=39; column>=0; column--) {
-        GPIO_CLR = 1<<SER_CLK_PIN;
         GPIO_ALTER(display_data -> buf[display_data -> is_buf][column] & (0x01 << line)) = 1<<SER_DAT_PIN;
+        GPIO_CLR = 1<<SER_CLK_PIN;
+        wait_tpic_settle_time
         GPIO_SET = 1<<SER_CLK_PIN;
+        wait_tpic_settle_time
 #endif // SKIP_GPIO
       }
 #ifdef SKIP_GPIO
diff --git a/multiplexer.h b/multiplexer.h
index 738d6ad..4f94f17 100644
--- a/multiplexer.h
+++ b/multiplexer.h
@@ -49,6 +49,8 @@ static uint8_t gpioToPUDCLK [] =
 
 #define SCROLL_BUF_LEN 4096
 
+#define wait_tpic_settle_time  for (int i=0; i<100; i++) { asm volatile("" : : "r" (i)); }
+
 int  mem_fd;
 void *gpio_map;
 
-- 
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