Difference: McForth (8 vs. 9)

Revision 92019-01-18 - PeterSchmid

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EEPROM Serial Communication

Serial Peripheral Interface SPI, MC is the SPI master, the host is the slave.

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e.g. AT25M02

SPI EEPROM 2Mbit (256 KiB, $3) or 25LC512 (64 KiB, $1.50). DIL8 Package. 256 KiB seems very small for today's standards where storage is quantified in GiB, but I think it's more than enough for a small Forth system.

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e.g. AT25M02

SPI EEPROM 2Mbit (256 KiB, $3) or 25LC512

(64 KiB, $1.50). DIL8 Package. 256 KiB seems very small for today's standards where storage is quantified in GiB, but I think it's more than enough for a small Forth system.

CLK   MC ->- host
MOSI  MC ->- host

Line: 163 to 163

SS MC ->- host or other peripherals (optional)

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A high-to-low transition on the CS pin is required to start an operation and a low-to-high transition is required to end an operation.

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Invalid Opcode: If an invalid opcode is received, no data will be shifted into AT25M02 and the Serial Data Output (SO) pin will remain in a high impedance state until the falling edge of CS is detected again. This will reinitialize the serial communication.

25LC512 Instruction Set

Name	Format	Description
READ	0000 0011	Read data from memory array beginning at selected address
WRITE	0000 0010	Write data to memory array beginning at selected address
WREN	0000 0110	Set the write enable latch (enable write operations)
WRDI	0000 0100	Reset the write enable latch (disable write operations)
RDSR	0000 0101	Read STATUS register
WRSR	0000 0001	Write STATUS register
PE	0100 0010	Page Erase – erase one page in memory array
SE	1101 1000	Sector Erase – erase one sector in memory array
CE	1100 0111	Chip Erase – erase all sectors in memory array
RDID	1010 1011	Release from Deep power-down and read electronic signature
DPD	1011 1001	Deep Power-Dow

AT25M02 Instruction Set

Name	Format	Description
LPWP	0000 1000	Low Power Write Poll
WREN	0000 0110	Set Write Enable Latch (WEL)
WRDI	0000 0100	Reset Write Enable Latch (WEL)
RDSR	0000 0101	Read Status Register (SR)
WRSR	0000 0001	Write Status Register (SR)
PE	0100 0010	Page Erase – erase one page in memory array
SE	1101 1000	Sector Erase – erase one sector in memory array

RDSR 0000 0101 (05h) Read Status Register (SR) Status Register Section 4.2.1 LPWP 0000 1000 (08h) Low Power Write Poll Status Register Section 4.2.2 WREN 0000 0110 (06h) Set Write Enable Latch (WEL) Status Register Section 4.3.1 WRDI 0000 0100 (04h) Reset Write Enable Latch (WEL) Status Register Section 4.3.2 WRSR 0000 0001 (01h) Write Status Register (SR) Status Register Section 4.4 READ 0000 0011 (03h) Read from Memory Array Memory Array Section 5. WRITE 0000 0010 (02h) Write to Memory Array Memory Array Section 6

Serial EEPROM Connected to Centronics Connector (Switches and LEDs)

Sharing the LED and Switch port, you loose two LEDs and one switch. Conflict with the bootstrap loader, some sort of disable EEPROM needed e.g. switch or jumper.

Line: 172 to 237

MISO	J2.9 IN7 SWITCH7	2 SO	direct
MOSI	J2.11 O7 LED7	5 SI	direct
CLK	J2.10 O6 LED6	6 SCK	direct

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1 CS

Pullup 10 k, switch to GND

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? O5 LED5

1 CS

Pullup 10 k, switch to GND

P4.3 VDD	8 VCC	+5V
"	3 WP	+5V
"	7 HOLD	+5V

Line: 189 to 254

MISO	/EF2	2 SO	direct
MOSI	D0	5 SI	direct
CLK	TPB & N1 (OUT2)	6 SCK	wired AND; Pullup 10 k, 2 1N4148

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1 /CS

GND

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1 /CS

GND

		8 VCC	+5V
		3 /WP	+5V
		7 /HOLD	+5V

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