APU для Spectrum -арифметический сопроцессор

[zx_]

набрел здесь на заметку, о подключении 8231 к спектруму, пишут из старого немецкого журнала
схемка



I'm probably able to give you some hints because of... a couple of weeks ago I started to build a Sinclair ZX / ZX81 APU Prototyp card based on an article of an old German computer magazin.
So even that the ROM seems to be missing on your card you are probably able to use the card with some Basic coding as we started here in Germany to do some simple tests.
APU Intel 8231A or AMD AM9511A are pin compatible
So beside some coding we started with using the original Spectrum ZX ROM without any changes:
Used I/O Addresses to communicate with the APU are as follows, while the APU is using two registers for the calculation(s): a Data- and a Command Register
D=Data-Adresse = 31d -> 1Fh (or 125d -> 7Dh)
C=Command-Adresse = 95d -> 5Fh (or 127d -> 7Fh)
in our case we toggle address bit A6 to switch between Data and Command register (see my attached schematic snapshoot), so the Apple I/O Addresses needs to be used here, instead.
APU Testprogramm using the Standard Speccy 48K ROM
Arithmetic APU Operation -> 16 Bit Addition: Command 108d -> 6Ch

PROGRAM: APU-Test
100 REM TESTPGM 8231A or AM9511A APU
110 LET C=95: LET D=31 REM 95d = Command Register; 31d = Data Register
120 OUT D,10: OUT D,0 REM load value 10 to the APU
130 OUT D,20: OUT D,0 REM load value 20 to the APU
140 OUT C,108 REM use APU command 108d -> 6Ch to do a 16nd Bit Addition
150 LET A=IN D: LET B=IN D REM get calculation result(s)
160 PRINT A REM A should held 0
160 PRINT B REM B should held 30 -> which is the result of 10 + 20 (see above)


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