Difference: McForth (11 vs. 12)

Revision 122019-01-19 - PeterSchmid

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EEPROM Serial Communication

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

Changed:

<
< 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.

>
> e.g. AT25M02 SPI EEPROM 2Mbit (256 KiB, $3), 25LC1024 (128 KiB, $2), or 25LC512 (64 KiB, $1.50). DIL8 Package. 64/128/256 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)

Changed:

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

>
> 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.

Changed:

<
< Invalid Opcode: If an invalid opcode is received, no data will be shifted into AT25M02 and the Serial Data

>
> 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.

Changed:

<
< 25LC512 Instruction Set

>
>

While in Hold mode, the SO pin will be in a high impedance state. In addition, both the SI pin and the SCK pin will be ignored.

25LC512 25LC1024 Instruction Set

Name	Format	Description

Changed:

<
<

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

>
>

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

Line: 186 to 189

AT25M02 Instruction Set

Name	Format	Description

Changed:

<
<

READ	0000 0011	Read from Memory Array
WRITE	0000 0010	Write to Memory Array
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)

>
>

READ	0000 0011	Read from Memory Array
WRITE	0000 0010	Write to Memory Array
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)

LPWP

0000 1000

Low Power Write Poll

Serial EEPROM Connected to Centronics Connector (Switches and LEDs)

Changed:

<
< Sharing the LED and Switch port, you loose two LEDs and one switch. Possible conflict with the bootstrap loader, if there is a read sequence (CS and read pattern 0000 0011).

>
> Sharing the LED and Switch port, you loose two LEDs and one switch. Possible conflict with the bootstrap loader, if there is a read sequence (CS and read pattern 0000 0011). To prevent this, set the EEPROM into HOLD state e.g. with the WAIT/ signal.

SPI	MC (Master)	AT25xxx (Slave)	Interface

Changed:

<
<

MISO

J2.9 IN7 SWITCH7 (IN? EF4)

2 SO

diode e.g. 1N4148

>
>

MISO

J2.1 /IN EF4

2 SO

diode e.g. 1N4148

MOSI	J2.11 O7 LED7	5 SI	direct
CLK	J2.10 O6 LED6	6 SCK	direct

Changed:

<
<

CS	J2.12 O5 LED5	1 CS	direct
	P4.3 VDD	8 VCC	+5V
	"	3 WP	+5V
	"	7 HOLD	+5V

>
>

CS	J2.12 O5 LED5	1 CS/	direct
	P4.3 VDD	8 VCC	+5V capacitor 100 nF to GND
	"	3 WP/	+5V
	J2.14 WAIT/	7 HOLD/	direct

21 GND

4 GND

GND

Raspberry Pi can emulate SPI EEPROM. On RaspiElf the switches/LEDs are already connected to Raspi's GPIOs. No need for additional hardware. But I have to write an SPI server for the Raspberry Pi.

Line: 237 to 240

CS	J2.11 O7 LED7	1 /CS	direct
		8 VCC	+5V
		3 /WP	+5V

Changed:

<
<

7 /HOLD

+5V

>
>

J2.14 WAIT/

7 /HOLD

direct

4 GND

GND

Line: 247 to 250

the file system on the host? No need to add additional hardware (SD-card is anyway to modern You could use an old CP/M or even a PDP11 as host. The C-Kermit Local Server mode, e.g. MC can read/write the blocks as files block.0, block.2, block.255.

Added:

>
> The serial communication is really slow, not only because of the 9600 baud, but you have to wait after each character to give CDP1802 some computation time.

https://github.com/utoh/pygmy-forth/blob/master/extras/kermit/pfkerm.doc

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