View source for SIMPLE-Z80

[[FILE:SIMPLE-Z80_P1090211-720PX.jpg]]

== Features ==

* Build of [http://searle.x10host.com/z80/SimpleZ80.html Grant Searles's Simple Z80 CPU]
** Runs BASIC
* [https://github.com/douggilliland/Retro-Computers/blob/master/Z80/Parts/Z80%20Family/Z80%20CPU%20z80b8400.pdf Z80 CPU]
* 7.3728 MHz clock
* [https://github.com/land-boards/lb-boards/blob/master/RetroCPUs/SIMPLE-Z80/PARTS/TC551001_128KB_SRAM_datasheet.pdf 56KB SRAM (uses 128KB parts)]
* [https://github.com/douggilliland/Retro-Computers/blob/master/Z80/Parts/EEPROMs/EEPROM%2028C64.pdf 8KB EPROM/EEPROM]
* [https://github.com/land-boards/lb-boards/blob/master/RetroCPUs/SIMPLE-Z80/PARTS/MC68B50_43633.pdf 68B50 Serial Port (ACIA)]
** [https://github.com/land-boards/lb-boards/blob/master/RetroCPUs/SIMPLE-6502/PARTS/max232.pdf RS-232 port]
** Header for FTDI
** 115,200 baud
* Reset switch with [https://github.com/land-boards/lb-boards/blob/master/RetroCPUs/SIMPLE-6502/PARTS/ds1813-maxim%20integrated%20products_1178753.pdf optional DS1813 Power Supervisor]
* 95x95mm card
* (4) 6-32 mounting holes

=== Memory Map ===

* 0x0000-0x1FFF 8KB ROM
* 0x2000-0xFFFF 56KB SRAM
* I/O
** 0x00-0x7F - Free
** 0x80-0x81 - Serial port (ACIA)

=== Chip Set ===

* [https://www.ebay.com/itm/113735638336?hash=item1a7b2c1d40:g:93YAAOSwtk9go5uR&amdata=enc%3AAQAHAAAA0CjeSaZOW7IJt0NyR2yD7ilWLBLOhIXrKXUX00mtG4N2pCKiMj2ZmWvR2eYttWQWGhbYch81xsx3t3XDAFpKv1snVQMDOs%2BgIIUlq7KnkxRtImp%2BHKApjKwXS2CA%2FK5U0uOJ5AZnC%2BUxA4UEO8fhLc%2BucWWgY%2FysZU1Idm861p60B08tFLK25hEEO169mFVVKWJFdFm5xmP5bQVAd2GQVMEuFisq9hjkeoXJAbZsJG5hj45aIJ8Ftau0KsGfYAV9OxmNkOFFz5%2FG586nm0AMR4Q%3D%7Ctkp%3ABk9SR-CEoMHpYA Ebay listing]
** Needs [https://www.ebay.com/itm/363470308952?var=632689151269 68B50] to run Grant's code

[[file:SimpleZ80_Chipset.jpg]]

== Design ==

* CPU

[[file:SIMPLE-Z80_U2_CPU.PNG]]

* EPROM

[[file:SIMPLE-Z80_U6_EPROM.PNG]]

* SRAM

[[file:SIMPLE-Z80_U4_SRAM.PNG]]

* ACIA

[[file:SIMPLE-Z80_U3_ACIA.PNG]]

* Clock

[[file:SIMPLE-Z80_U5_CLK.PNG]]

== Headers / Connectors ==

[[FILE:SIMPLE-Z80_REV1_CAD.PNG]]

=== J1 - RS-232 Serial ===

* DB-9 Male
* Pinout

# N/C
# Receive
# Transmit
# Loop to pin 6
# GND
# Loop to pin 4
# RTS
# N/C
# N/C

=== J2/J5 - EPROM/EEPROM Select Jumpers ===

[[FILE:SIMPLE-Z80_J2_J5.PNG]]

* J2 - EPROM Pin 1 jumper
** 1-2 for 28C64, 28C256 (Pull WE to VCC)
** 2-3 for 27256, 27SF256, 27512 (Pull A14 to GND)
* J5 - EPROM Pin 27 jumper
** GND (2-3)

==== EEPROM Pin Table ====

{| class="wikitable"
! 27512
! 27256
! 27SF256
! 28C256
! 27128
! 2764
! 28C64
! PIN
! 
! PIN
! 2764
! 28C64
! 27128
! 28C256
! 27SF256
! 27256
! 27512
|-
| A15
| VPP
| VPP
| A14
| VPP
| VPP
| N/C
| 1
| 
| 28
| VCC
| VCC
| VCC
| VCC
| VCC
| VCC
| VCC
|-
| A12
| A12
| A12
| A12
| A12
| A12
| A12
| 2
| 
| 27
| PGM
| WE*
| PGM
| WE*
| A14
| A14
| A14
|-
| A7
| A7
| A7
| A7
| A7
| A7
| A7
| 3
| 
| 26
| A13
| N/C
| A13
| A13
| A13
| A13
| A13
|-
| A6
| A6
| A6
| A6
| A6
| A6
| A6
| 4
| 
| 25
| A8
| A8
| A8
| A8
| A8
| A8
| A8
|-
| A5
| A5
| A5
| A5
| A5
| A5
| A5
| 5
| 
| 24
| A9
| A9
| A9
| A9
| A9
| A9
| A9
|-
| A4
| A4
| A4
| A4
| A4
| A4
| A4
| 6
| 
| 23
| A11
| A11
| A11
| A11
| A11
| A11
| A11
|-
| A3
| A3
| A3
| A3
| A3
| A3
| A3
| 7
| 
| 22
| OE*
| OE*
| OE*
| OE*
| OE*
| OE*
| OE*
|-
| A2
| A2
| A2
| A2
| A2
| A2
| A2
| 8
| 
| 21
| A10
| A10
| A10
| A10
| A10
| A10
| A10
|-
| A1
| A1
| A1
| A1
| A1
| A1
| A1
| 9
| 
| 20
| CE*
| CE*
| CE*
| CE*
| CE*
| CE*
| CE*
|-
| A0
| A0
| A0
| A0
| A0
| A0
| A0
| 10
| 
| 19
| D7
| D7
| D7
| D7
| D7
| D7
| D7
|-
| D0
| D0
| D0
| D0
| D0
| D0
| D0
| 11
| 
| 18
| D6
| D6
| D6
| D6
| D6
| D6
| D6
|-
| D1
| D1
| D1
| D1
| D1
| D1
| D1
| 12
| 
| 17
| D5
| D5
| D5
| D5
| D5
| D5
| D5
|-
| D2
| D2
| D2
| D2
| D2
| D2
| D2
| 13
| 
| 16
| D4
| D4
| D4
| D4
| D4
| D4
| D4
|-
| GND
| GND
| GND
| GND
| GND
| GND
| GND
| 14
| 
| 15
| D3
| D3
| D3
| D3
| D3
| D3
| D3
|-
|}

=== J3 - FTDI / TTL Serial ===

* Requires a FTDI cross-over cable

[[file:SIMPLE-Z80_J3_FTDI.PNG]]

* Pinout
# GND
# N/C
# +5V
# Transmit (out)
# Receive (in)
# RTS* (out)

=== J4 - 5V Power ===

* 2x4 header

[[file:SIMPLE-Z80_J4_PWR.PNG]]

== First Unit Checkout ==

* PCB

[[FILE:SIMPLE-Z80_P1090181-720px.jpg]]

=== Install Sockets ===

* Machined pin sockets

=== Install Passives ===

=== Power ===

* Install 2x4 at J4
* Power card via J4 with 5V
* Check power pins on parts

=== Clock ===

* Install Clock parts
** Install R2, R3
** Install C5, C6
** Install 7.3728 MHz crystal
** Install 74HC04 at U5
* Measure clock at U5-4
** 7.32 MHz clock - looks good

=== Reset ===

* Do not install U8 Power Monitor
** Reset button gets stretched by Power Monitor U9
* Install pushbutton switch SW1
* Measure reset at Z80 U2 pin marked RST on silkscreen

[[FILE:SIMPLE-Z80_P1090202-720PX.jpg]]

=== EPROM ===

* U6 = SST27C256 EEPROM
** 32 KB part
** Using first 16KB of EEPROM
** J2 EEPROM pin 1 = VPP = VCC or GND
*** Jumper J2:2-3
** J5 EEPROM pin 27 = A14 = GND 
*** Jumper J5:2-3

==== EEPROM Programming ====

* Program using [[TL866ii_Plus_Programmer|TL-866ii plus programmer]]
* File = [https://github.com/land-boards/lb-boards/blob/master/RetroCPUs/SIMPLE-Z80/SOFTWARE/ROM.HEX ROM.HEX] - I/O routines plus BASIC
* Got Device ID error
* Turn off ID check

[[file:SIMPLE-6502_TL866Plus_Program.png]]

* Device programmed/verified

=== Install CPU, ROM, RAM, ACIA ===

* U1 - Do not install MAX232 yet
** Use FTDI connector with [[FTDI-49MM]] card

=== Test FTDI Serial ===

* Wiring is '''not''' 1:1 to [[FTDI-49MM]]
* Wire FTDI J3 to [[FTDI-49MM]] card
** [[FTDI-49MM]] GND pin 1 to J3-1 RX on card
** [[FTDI-49MM]] VCC pin 3 to J3-3 RX on card
** [[FTDI-49MM]] TX pin 4 on to J3-5 RX on card
** [[FTDI-49MM]] RX pin 5 on to J3-4 TX on card
** [[FTDI-49MM]] CTS(in) pin 2 to J3-6 CTS on card

[[FILE:SIMPLE-Z80_P1090211-720PX.jpg]]

=== Test RS-232 Serial ===

* With MAX232
* Install DB-9 Male
* Holes don't line up well, but 4-40 screws can fit
* Connected to [[FTDI-49MM]] and [[DCE]] cards
** [[FTDI-49MM]] and [[DCE]] cards wired together
** [[DCE]] has female DB-9
** Separate power cable J2 on [[FTDI-49MM]] to J3 on card

[[FILE:FTDI_DCE_P1090192-720PXV.jpg]]

* Works

=== Netlist ===

<pre>
/CPUA0,U2-30,U3-11,U4-12,U6-10,
/CPUA1,U2-31,U4-11,U6-9,
/CPUA2,U2-32,U4-10,U6-8,
/CPUA3,U2-33,U4-9,U6-7,
/CPUA4,U2-34,U4-8,U6-6,
/CPUA5,U2-35,U4-7,U6-5,
/CPUA6,U2-36,U3-9,U4-6,U6-4,
/CPUA7,U2-37,U3-10,U4-5,U6-3,
/CPUA8,U2-38,U4-27,U6-25,
/CPUA9,U2-39,U4-26,U6-24,
/CPUA10,U2-40,U4-23,U6-21,
/CPUA11,U2-1,U4-25,U6-23,
/CPUA12,U2-2,U4-4,U6-2,
/CPUA13,U2-3,U4-28,U6-26,U7-9,
/CPUA14,U2-4,U4-3,U7-10,
/CPUA15,U2-5,U4-31,U7-13,
/CPUCLK,U2-6,U3-3,U3-4,U5-4,
/CPUD0,U2-14,U3-22,U4-13,U6-11,
/CPUD1,U2-15,U3-21,U4-14,U6-12,
/CPUD2,U2-12,U3-20,U4-15,U6-13,
/CPUD3,U2-8,U3-19,U4-17,U6-15,
/CPUD4,U2-7,U3-18,U4-18,U6-16,
/CPUD5,U2-9,U3-17,U4-19,U6-17,
/CPUD6,U2-10,U3-16,U4-20,U6-18,
/CPUD7,U2-13,U3-15,U4-21,U6-19,
/CPUIORQ*,U2-20,U5-5,
/CPUM1,U2-27,U3-8,
/CPUMREQ*,U2-19,U7-2,U7-4,
/CPURD*,U2-21,U7-5,
/CPUWR*,U2-22,U3-13,U7-1,
/EE_PIN1,J2-2,U6-1,
/EE_PIN27,J5-2,U6-27,
/F-RTS*,J3-6,R5-2,
/F_RX,J3-5,R6-2,
/F_TX,J3-4,R7-2,
/IORQ,U3-14,U5-6,
/IRQ*,R4-2,U2-16,U3-7,
/MEMRD*,U4-24,U6-22,U7-6,
/MEMWR*,U4-29,U7-3,
/ROM0RAM1,U4-30,U6-20,U7-11,
/RS_RTS*,J1-7,U1-14,
/RS_RX,J1-2,U1-8,
/RS_TX,J1-3,U1-7,
/RTS*,R5-1,U1-11,U3-5,
/UART_RX,R6-1,U1-9,U3-2,
/UART_TX,R7-1,U1-10,U3-6,
/~{CPURESB},R1-2,SW1-2,U2-26,U8-1,
GND,C10-1,C11-1,C12-1,C13-1,C14-2,C3-2,C4-1,C5-2,C6-2,C7-1,C8-1,C9-1,J1-5,J2-3,J3-1,J4-1,J4-3,J4-5,J4-7,J5-3,SW1-1,U1-15,U2-29,U3-1,U3-23,U3-24,U4-16,U4-2,U4-22,U5-7,U6-14,U7-7,U8-3,
Net-(C5-Pad1),C5-1,R3-1,Y1-2,
Net-(C6-Pad1),C6-1,R2-1,U5-1,Y1-1,
Net-(J1-Pad4),J1-4,J1-6,
Net-(R2-Pad2),R2-2,R3-2,U5-2,U5-3,
Net-(U1-C1+),C1-1,U1-1,
Net-(U1-C1-),C1-2,U1-3,
Net-(U1-C2+),C2-1,U1-4,
Net-(U1-C2-),C2-2,U1-5,
Net-(U1-VS+),C3-1,U1-2,
Net-(U1-VS-),C4-2,U1-6,
Net-(U7-Pad12),U7-12,U7-8,
VCC,C10-2,C11-2,C12-2,C13-2,C14-1,C7-2,C8-2,C9-2,J2-1,J3-3,J4-2,J4-4,J4-6,J4-8,J5-1,R1-1,R4-1,U1-16,U2-11,U2-17,U2-24,U2-25,U3-12,U4-32,U5-11,U5-13,U5-14,U5-9,U6-28,U7-14,U8-2,
</pre>

== Software ==

* [https://github.com/land-boards/lb-boards/blob/master/RetroCPUs/SIMPLE-Z80/SOFTWARE/ROM.HEX ROM.HEX] - ROM file
* Nascom 2 Computer BASIC Microsoft BASIC 4.7 modified to remove all hardware-specific code

=== Source files ===

* intmini.asm - the interupt driven mini startup program needed to boot into BASIC
* basic.asm - BASIC 4.7b - a conversion of Microsoft BASIC 4.7, as used on the Nascom computers (see below for details)

=== Output files ===

* INTMINI.HEX
* BASIC.HEX
* ROM.HEX - the complete 8K ROM ready for burning to an EPROM - the unused contents are filled with FF values.
* Within the ROM, the serial handler is first (starting at address 0000H), followed by the BASIC interpreter (starting at 0100H).

=== Assembler files (for Windows/DOS) ===

* _ASSEMBLE.BAT - double-click in Windows to run the assembly if needed
* TASM.EXE
* TASM80.TAB

=== Acknowledgements ===

* BASIC is Microsoft BASIC 4.7 for the NASCOM, heavily modified by Grant to remove references to different monitors, screen handlers and keyboard matrix reading
* TASM assembler is a partial distribution of the package from Speech Technology Incorporated

== Performance ==

* TeraTerm settings

[[file:SIMPLE-6809_TeraTerm_Setup.PNG]]

* Test software

<pre>
10 FOR I =1 TO 10000
20 PRINT I
30 NEXT I

</pre>

* Time ~ secs

== Mechanicals ==

[[FILE:SIMPLE-Z80_REV1_MECHS.PNG]]

== SIMPLE-Z80 Assembly Sheet ==

* [[SIMPLE-Z80 Rev 1 Assembly Sheet]]
* [http://land-boards.com/SIMPLE-Z80/SIMPLE-Z80_Rev1_ibom.html SIMPLE-Z80 Rev 1 Interactive BOM]