Interfacing MMC/SD/SDSC/SDHC cards

This page contains basic information including the circuit and the basic program needed to test the MMC/SD/SDSC/SDHC cards interface implementation, that is a part of the Basic compiler special functions pack 1 add-on module, available for PIC18 Simulator IDE, PIC16 Simulator IDE, PIC Simulator IDE and AVR Simulator IDE applications from the OshonSoft.com IDEs suite.

SCHEMATICS

SCHEMATICS:

Here is one of the simplest examples written in OshonSoft PIC Simulator IDE basic that still demonstrates all the functionality of the MMC/SD/SDSC/SDHC cards interface implementation. Its intended usage is to be programmed into the 16F876A chip that is used in the test circuit.

Interfacing MMC/SD/SDSC/SDHC cards test basic program:

Define CONFIG = 0x3f72
Define CLOCK_FREQUENCY = 20
Define SDCARD_DEFAULT_WRITE = 0x00

Define LCD_LINES = 4
Define LCD_CHARS = 20
Define LCD_BITS = 4
Define LCD_DREG = PORTB
Define LCD_DBIT = 4
Define LCD_EREG = PORTB
Define LCD_EBIT = 3
Define LCD_RSREG = PORTB
Define LCD_RSBIT = 2

Define SPI_CS_REG = PORTC
Define SPI_CS_BIT = 2
Define SPI_SCK_REG = PORTC
Define SPI_SCK_BIT = 3
Define SPI_SDI_REG = PORTC
Define SPI_SDI_BIT = 4
Define SPI_SDO_REG = PORTC
Define SPI_SDO_BIT = 5

Dim block As Byte
Dim num As Word
Dim var1 As Byte
Dim var2 As Byte
Dim var3 As Byte
Dim var4 As Byte
Dim var5 As Byte
Dim var6 As Byte
Dim var7 As Byte
Dim var8 As Byte

AllDigital
Lcdinit LcdCurBlink

WaitMs 2000
Lcdcmdout LcdClear
Lcdout "SD CARDS TEST!"
Lcdcmdout LcdCurOff

SDCardInit

block = 1
do_again:

WaitMs 2000
Lcdcmdout LcdClear
If sd_status.sd_error = 1 Then Lcdout "Unknown card!"
If sd_status.sd_mmc = 1 Then Lcdout "MMC card!"
If sd_status.sd_sd = 1 Then Lcdout "SD card!"
If sd_status.sd_sdsc = 1 Then Lcdout "SDSC card!"
If sd_status.sd_sdhc = 1 Then Lcdout "SDHC card!"

WaitMs 2000
Lcdcmdout LcdLine2Clear
SDCardWriteStart block
For num = 0 To 511
	SDCardWriteByte num
Next num
SDCardWriteFinish
If sd_status.sd_rw_error = 1 Then Lcdout "Write error!"
If sd_status.sd_rw_error = 0 Then Lcdout "Block written!"

WaitMs 2000
SDCardReadStart block
For num = 0 To 63
	SDCardReadByte var1
	SDCardReadByte var2
	SDCardReadByte var3
	SDCardReadByte var4
	SDCardReadByte var5
	SDCardReadByte var6
	SDCardReadByte var7
	SDCardReadByte var8
	Lcdcmdout LcdLine3Clear
	Lcdout #var1, ",", #var2, ",", #var3, ",", #var4
	Lcdcmdout LcdLine4Clear
	Lcdout #var5, ",", #var6, ",", #var7, ",", #var8
	WaitMs 250
Next num
SDCardReadFinish
Lcdcmdout LcdLine4Clear
Lcdcmdout LcdLine3Clear
If sd_status.sd_rw_error = 1 Then Lcdout "Read error!"
If sd_status.sd_rw_error = 0 Then Lcdout "Block read!"

WaitMs 2000
If block = 1 Then
	block = 2
	Goto do_again
Endif
End

Interfacing MMC/SD/SDSC/SDHC cards test schematics:

2021 - 20th Anniversary of theOSHONSOFT PROJECTOshonSoft © 2001 - 2025

Interfacing MMC/SD/SDSC/SDHC cards

2021 - 20th Anniversary of the
OSHONSOFT PROJECT
OshonSoft © 2001 - 2025