The TE-1506 memory module is an important step on the way to the PC-1560.
It’s Sharp PC-1500(A) compatible and offers some nice features that missed from a long time.
I have ordered the prototype board and will receive it in two weeks.
In the size of a module you’ll have a 32KB static RAM and a 32KB Xicor EEPROM.
Now let’s see how it works :
The RAM :
It’s divided in two 16KB memory spaces from &0000H to &3FFFH and will replace your CE-161 module.
The LH5801 provide 2 flip-flops named PU and PV. They are mainly used to switch extension’s ROMs located from &8000H to &BFFFH.
Here you will be able to configure by jumper if pages are selected by PU or PV.
Natively the Basic can’t switch the RAM pages but… we will teach him.
For information the TRAMSoft memory extension use same page selection.
The whole RAM (from &0000H to &3FFFH) can be write protected by removing a jumper.
The EEPROM :
Xicor offers us a the perfect solution to store ROM extensions.
First, it’s 5v programable, second, it’s byte erasable !
No need of external EPROM programmer.
CGH already tested the Xicor solution on his PC-1500 as a permanent RAMDisk.
The 32KB of our EEPROM can work in two modes :
1 – As two 16KB ROM extensions located from &8000H to &BFFFH.
Depending on the peripheral used (CE-150 or CE-158) you can select the EEPROM’s position in the memory space.
If you use the CE-150 printer/tape interface then you have to select PU=1
If you use the CE-158 RS-232C/Parallel interface then you have to use PU=0
The two 16KB pages are selected by PV flip-flop.
Do you remember CGH’s tools ? BASWORD will be your friend.
2 – As a 16KB ROM extension + 16KB system ROM replacement.
The first 16KB page becomes the new system ROM and the second 16KB page is still a ROM extension located on PV=0 or PV=1 zone.
The whole EEPROM can be write protected by removing a jumper.
Amazing, no ? This will offer a solution to create you own root system !
Could you image a Forth native PC-1500 ?
an assembler native PC-1500 ?
a C native PC-1500 ?
First tests in 3 weeks !