Added pin definitions for SD card interface. Fixed bug in 6522 shift-register implementation (shift on CB1 rising edge should occur even in SR disabled mode). Works with MMBEEB SD card interface ROM.

1 files changed, 19 insertions, 5 deletions

diff --git a/bbc_micro_de1.vhd b/bbc_micro_de1.vhd
index a32d934..77922e2 100644
--- a/bbc_micro_de1.vhd
+++ b/bbc_micro_de1.vhd
@@ -90,6 +90,12 @@ port (
 	FL_WE_N		:	out		std_logic;

 	FL_CE_N		:	out		std_logic;

 	

+	-- SD card (SPI mode)

+	SD_nCS		:	out		std_logic;

+	SD_MOSI		:	out		std_logic;

+	SD_SCLK		:	out		std_logic;

+	SD_MISO		:	in		std_logic;

+	

 	-- GPIO

 	GPIO_0		:	inout	std_logic_vector(35 downto 0);

 	GPIO_1		:	inout	std_logic_vector(35 downto 0)

@@ -912,7 +918,7 @@ begin
 		"00" when mos_enable = '1' else

 		"01" when rom_enable = '1' and romsel(1 downto 0) = "11" else	-- BASIC

 		"10" when rom_enable = '1' and romsel(1 downto 0) = "00" else	-- DFS

-		"11";

+		"11"; -- MMC ROM

 		

 	-- SRAM bus

 	SRAM_UB_N <= '1';

@@ -1017,7 +1023,15 @@ begin
 	

 	-- Connections to User VIA (user port is output on green LEDs)

 	user_via_ca1_in <= '1'; -- Pulled up

-	LEDG <= user_via_pb_out;

+	--LEDG <= user_via_pb_out;

+	

+	-- MMBEEB

+	user_via_cb1_in <= user_via_pb_out(1);

+	SD_SCLK <= user_via_pb_out(1); -- SCLK

+	SD_MOSI <= user_via_pb_out(0); -- SDO

+	SD_nCS <= '0'; -- CS

+	user_via_cb2_in <= SD_MISO; -- SDI

+	user_via_pb_in <= user_via_pb_out;

 	

 	-- ROM select latch

 	process(clock,reset_n)

@@ -1060,8 +1074,8 @@ begin
 	-- DEBUG STUFF

 	-----------------

 	

-	GPIO_0(0) <= cpu_irq_n;

-	GPIO_0(1) <= keyb_out;

-	GPIO_0(2) <= keyb_enable_n;

+	GPIO_0(0) <= user_via_pb_out(1); --clk

+	GPIO_0(1) <= user_via_pb_out(0); --do

+	GPIO_0(2) <= SD_MISO; -- di

 

 end architecture;