6660611-64MB-MMC-and-PIC-Micro-Controller.pdf

64MB MMC and PIC Microcontroller

MMC memory card with PIC16F877 letter of a Multimedia Card (MMC) at each

PIC Mikrocontroller /Lesen over mirror-image interface (MMC 64MB and PIC

Microcontroller) a software related mirror-image interface makes possible the

connection. Connection diagram, theory about mirror-image interface, theory

about MMC, signal diagrams, program in C (CC5X).

MMC (Multimedia Card) here

64MB.

- Enormous FLASH - memory.

- Very fast.

-300000 write accesses.

- Vintages without restriction.

- Connection to the SPADES with 4

lines.

The PIC16F877 has:

- Mirror-image interface

- RS232 interface

- of 8 entrances for the similar to/digital

transducer (10Bit)

Pin Contraction Function

1 /CS

Chip activating

18 RC2

Digitally OUT

2 DATA IN Data input

24 SDO

MIRROR-IMAGE data

output

3 GND

4 Vdd

Voltage supply

5 CLK

Clocking line

18 SCL

MIRROR-IMAGE

Clock

6 GND

7 DATA OUT Data output

23 SDI

MIRROR-IMAGE data

input

Circuit and connection diagram MMC need as voltage supply 2,7V 3,6V. We

must use an in any case voltage regulator for 3,3V, for example CS5203. PIC

processors can be operated with tensions between 2V and 5,5V. Thus one

could agree with the supply of both units on 3,3V. Then it is also possible to

connect MMC directly with the micro CONTROLLER. Due to considerations that

the AD transducer and serial communication with 5V functions more stably it is

operated, in this circuit of the PIC16F877 nevertheless with 5V. But the micro

CONTROLLER exits SDO, SCL, /CS get in each case a voltage divider, so that

the MMC entrances receive only 3,2V. The entrances of the microprocessor do

not need reinforcement of 3,3V on 5,0V, because the PIC understands 3,3V

anyway as logical "1"

How does MIRROR-IMAGE ONE actually function? MIRROR-IMAGE ONE is a

serial synchronous interface. It means synchronous that each bit is

received/sent during a clock pulse

In the picture we see a register, where a byte will receive sent and. There were

2 clock pulses to bit 7 and bit 6 is sent over OUT. And 2 bits (also 7, 6) from new

byte receive. After 8 clock pulses the byte which can be sent is completely

"raus" and the received byte complete in the register. If the PIC works as

master, then it produces the clock pulses, which a Slave equipment needs to be

able to receive in order to push in time its register and thus send correct bits/.

With PIC Microcontrollern it is sufficient to transfer into the SSPBUF register a

byte, thus it begins this byte to send and a new receive. One may select

however not too early (while it pushes data) SSPBUF. Therefore we examine

the BF flag, it are reset during the transmission procedure. MMC one may to

20MHz clocks (CLK).

The MIRROR-IMAGE interface of the PIC can be stopped maximally to 5MHz. If

one has however long lines between PIC and MMC, then one must stop the

clock frequency lower, otherwise the signal form gets broken and it to happen

the errors. (with me there is 15cm lines).

The

following diagram shows attitude possibilities for MIRROR-IMAGE interfaces

with PIC's

MMC initializing in mirror-image mode

0 tension 1 sending 80 clock pulses 2 /CS activating, /CS=0, (1 passively) 3

sending CMD0 4 confirmation byte = 0x01? if no ERROR if 5 sends 8 clock

pulses

to 6 sending CMD1 7 confirmation byte = 0x00?wenn no go to 6 if 8 send 8

clock pulses MMC initialization into mirror-image mode finally

Executable program, description of function

This function serves for spending messages. In

order to send an indication serially, these

instructions are used. Function sends b over

MIRROR

SerString("Hallo Welt")

This function serves for spending messages. In

order to send an indication serially, these

instructions are used. Function sends b over

MIRROR

while (!TXIF); //_ Prüfen ob

TXREG ='W'; // Buchstabe "W"

seriell senden

This function serves for spending messages. In

order to send an indication serially, these

instructions are used. Function sends b over

MIRROR

a=SPI(b);

Command(0x49,0,512,0xFF );

This function serves for spending messages. In

order to send an indication serially, these

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