Z80 STI RS232 interface - Revision history

Ygdrazil at 10:35, 26 August 2014

2014-08-26T10:35:46Z

2011-04-29T20:50:23Z

‎Intro: - anonymized image name

2011-04-29T20:44:17Z

2010-08-09T19:35:19Z

‎Intro

2010-05-13T22:31:49Z

‎Intro

2010-05-11T12:12:28Z

‎Schematic and source code

2010-05-10T21:36:17Z

‎Intro

2010-05-10T20:58:49Z

‎Used components:

2010-05-10T19:35:41Z

‎About the assembler code

2010-05-10T19:35:16Z

‎About the assembler code

← Older revision		Revision as of 10:35, 26 August 2014
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	[[File:Rs232cpc.lzh]] - All info and files on topic		[[File:Rs232cpc.lzh]] - All info and files on topic
		+
		+	[[Category:Peripherals]]

@@ Line 11: / Line 11: @@
 Image:SchneiderSioManualPage2.jpg|Schneider's Schematic (1985)
 Image:NoPicture.png|Paul Bauriedl's Schematic (1987)
-Image:Tim Riemann RS232.gif|Tim Riemann's Schematic (1996)
+Image:Tim Riemann RS232.gif|Z80 STI Schematic (1996)
 </gallery>

@@ Line 5: / Line 5: @@
 The circuit is nearly indentical to the [[Schneider RS232 Interface]] from 1985, both circuits are using a [[Media:Mostek_3801_Data.pdf|Z80 STI]], both mapped to the same I/O port addresses. Both circuits are driven by the 4MHz signal on the CPC's expansion port, and connect CTS/RTS/DSR/DTR to the same pins, so they are (almost) 100% compatible. Some differences:
 * The Schneider circuit additionally implements CHRDET.
-* The Schneider circuit contains 2 diodes and 2 diodes for converting ~8V AC to +/-8V DC.
+* The Schneider circuit contains 2 diodes and 2 capacitors for converting ~8V AC to +8V/-8V DC.
 * The Schneider circuit uses only 2 chips for port decoding (the overcomplicated DIY uses 5 chips for exactly the same purpose)

@@ Line 1: / Line 1: @@
 == Intro ==
-This interface was originally described in the book "[[Maschinenspracheprogramme und Hardware-Erweiterungen für Schneider CPC's]]" written by [[Paul Bauriedl]], released by IDEA Verlag in 1987. Around mid-nineties, Tim Riemann has circulated the schematic as GIF in the internet.
+This interface was originally described in the book "[[Maschinenspracheprogramme und Hardware-Erweiterungen für Schneider CPC's]]" written by [[Paul Bauriedl]], released by IDEA Verlag in 1987. Around mid-nineties, it was turned into a single package and circulated in the internet.
 The circuit is nearly indentical to the [[Schneider RS232 Interface]] from 1985, both circuits are using a [[Media:Mostek_3801_Data.pdf|Z80 STI]], both mapped to the same I/O port addresses. Both circuits are driven by the 4MHz signal on the CPC's expansion port, and connect CTS/RTS/DSR/DTR to the same pins, so they are (almost) 100% compatible. Some differences:

@@ Line 20: / Line 20: @@
 First about the connection plan: You need a power supply that supports +9V,-9V and 5V. Connect all pins. You have to connect D0..D7 from the adressbus with the Z80 STI. You have to connect D0 with pin 21, D1 with pin 22, ..., D7 with pin 28. That's all.
 Now you can plug in the interface in the CPC. Switch the power on. If the CPC doesn't work normal please switch the power off and you have to watch for faults in the connection of your interface :-(. If everything is ok then you have to copy the assembler code and do the next test.
 Second part: How to program the interface. (The assembler code is saved in RS232.ASM)

← Older revision	Revision as of 20:44, 29 April 2011
(No difference)

@@ Line 3: / Line 3: @@
 This interface was originally described in the book "[[Maschinenspracheprogramme und Hardware-Erweiterungen für Schneider CPC's]]" written by [[Paul Bauriedl]], released by IDEA Verlag in 1987. Around mid-nineties, Tim Riemann has circulated the schematic as GIF in the internet.
-The circuit is nearly indentical to the [[Schneider RS232 Interface]] from 1985, both circuits are using a [[Media:Mostek_3801_Data.pdf|Z80 STI]], both mapped to the same I/O port addresses. Both circuits seem to be driven by the 4MHz signal on the CPC's expansion port, so even the the timings should be 100% compatible. The only difference is that the DIY circuit uses more logic chips for decoding of the I/O port addresses (the extra chips are just more over-complicated, not actually better). Another difference, concerning the power supply, is that the Schneider circuit contains 2 diodes and 2 diodes for converting ~7V AC to +/-7V DC.
+The circuit is nearly indentical to the [[Schneider RS232 Interface]] from 1985, both circuits are using a [[Media:Mostek_3801_Data.pdf|Z80 STI]], both mapped to the same I/O port addresses. Both circuits are driven by the 4MHz signal on the CPC's expansion port, and connect CTS/RTS/DSR/DTR to the same pins, so they are (almost) 100% compatible. Some differences:
 <gallery>

@@ Line 155: / Line 155: @@
 Note: The 74LS20, 74LS04, 74LS32 are the smaller logic symbols in the schematic.
-Note 2: The 74LS138 splits the address space to four regions (which is total nonsense), the 74LS20 is then merging them back to a single region (which is undoing that nonsense). There seems to be no real reason for doing that - except maybe to avoid legal copyright problems (claiming something like "no this isn't a unlicensed remake of Schneider's schematic, our schematic is doing total nonsense, it's has absolutely nothing to do with Schneider's hardware").
+Note 2: The 74LS138 splits the address space to four regions (which is total nonsense), the 74LS20 is then merging them back to a single region (which is undoing that nonsense). Although the 74LS138 is rather useless in this case, the book from Paul Bauriedl contains further schematics, in which the 74LS138 does have some purpose.
 == Downloads ==
 [[File:Rs232cpc.lzh]] - All info and files on topic

@@ Line 122: / Line 122: @@
 = 1200 bps
 = 2400 bps
-−
   Number of stop bits: 1 = 1 stop bit
 = 2 stop bit
-−
   Data bits:           0 = 7 data bits
 = 8 data bits
-−
   Parity even/odd:     1 = even
 = odd
-−
   Parity on/off:       1 = on
 = off

@@ Line 114: / Line 114: @@
 '''|FORMAT''', number of bps, number of stop-bits, data bits, parity on/off, parity even/odd
-Number of bps:
+ Number of bps:       0 =   50 bps
-=   50 bps
+ Number of stop bits: 1 = 1 stop bit
-=   75 bps
+= 2 stop bit
-=  110 bps
-=  150 bps
-=  300 bps
-=  600 bps
-= 1200 bps
-= 2400 bps
-Number of stop bits: 1 = 1 stop bit
+ Data bits:           0 = 7 data bits
-= 2 stop bit
+= 8 data bits
-Data bits:           0 = 7 data bits
+ Parity even/odd:     1 = even
-= 8 data bits
+= odd
-Parity:              1 = even
+ Parity on/off:       1 = on
-= odd
+= off
-Parity:              1 = on
+Normally, you use 8N1 for connection with BBS's you can initialise this with |FORMAT, number of bps, 1, 1, 0, 1.
-= off
-Normally, you use 8N1 for connection with BBS's you can initialise this with
+'''|RECORD, @a$''' - The incoming chars will be read in a string. Control codes will be send to the string, too, because sometimes you need it for binary transmissions.
-|FORMAT, number of bps, 1, 1, 0, 1.
-−
-−
-'''|RECORD''', @a$
 The incoming chars will be read in a string. Control codes will be send to the
-string, too, because sometimes you need it for binary transmissions.
-−
-−
-'''|SEND''', @a$
-The string is send until it ends, except you press ESC. The program will not
-send CR or LF, so you can use this for binary transmission.
 == Used components: ==