Microwire Eeprom - 93C46
Microwire Eeprom - SPI - 93C46
Fig. 1 Microwire Eeprom 93C46
Description:
This board is a Microwire Eeprom, with an SPI interface. It is based around a Microwire serial EEPROM, like 93C06 or 93C46.
It connects to a host with an SPI bus, up to 1 MHz.
The memory available depends on the chip used. It is 1024 bits, organised as 64 words of 16 bits on a 93C46.
The interface is Microwire, which is close to SPI, and can be implemented with the SPI interface of the tutorials. The main difference is that the clock is limited to 1 MHz, CS is active high, and the communication is not on a multiple of 8 bits.
The board can be powered from 2.7 to 5V.
Schematic:
Specifications:
Input voltage 2.7 to 5V
Interface Microwire 1MHz
CS selectable by jumper
MemoryDepends on chip
1K with 93C46
The schematic is straight forward. U1 is connected to the SPI interface with its various signals (MISO, MOSI, SCK, CS) on K1. Jumper J1 allows to select between CS0, CS1 or CS2 from the SPI interface to drive the chip. CS is active high, so R1 pulls it low by default.
U1 can be selected from the various Microwire eerom family 93Cx6: 93C06, 93C46, 93C56...
R2 is here to have an easy Gnd point to connect a test instrument.
Fig. 2 Microwire Eeprom schematic
Construction:
The PCB fits on a small single sided board. All components are on the top side.
Fig. 3 Microwire Eeprom layout
Start with the lowest components, and continue with the higher ones on the top side.
R2 is made up of a piece of resistor's lead. It's here to easily attach a clip from a test instrument or have a Gnd test point.
Pads 1 to 4 can be drilled to 3mm to fix the board, or put spacers.
| Microwire Eeprom Component list |
|---|
| C1: 100 nF R1: 100 K R2: resistor's lead U1: 93Cx6 memory chip (93C46) + 8 pins DIL socket J1: jumper 3x2 K1: Connector AMP MT 8 pins male |
How to use / Testing:
To check the board, connect the board to an SPI interface. Leave jumper off J1 for now. Power up the board.
Check you have the Vcc supply between pin 5 and 8 of U1 socket.
To check the Eeprom is working, you need a processor board running the Microwire Eeprom tutorial. Just make sure you set the switch on J1 to the proper CS line.
Files and links:
Eagle PCB and schematics files for Microwire Eeprom.PDFs of PCB, layout and schematics of Microwire Eeprom.
PIC Tutorials for Microwire Eeprom.
Microwire 93C46.