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telephony:ta1232_td816_td1232_hw_arch [2025/04/19 23:03] – [CPU and general architecture] prppedrotelephony:ta1232_td816_td1232_hw_arch [2025/04/19 23:42] (current) – [Memory] prppedro
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 {{ :telephony:toshiba_tmp68301af-12_cpu.jpg?400 |}} {{ :telephony:toshiba_tmp68301af-12_cpu.jpg?400 |}}
  
-While the CPU might be different between versions (newer models do operate at 12 MHz, in contraposition to older models at 8 MHz), the pinout seems to be largely the same in all three versions. +While the CPU might be different between versions (newer KX-TD models do operate at 12 MHz, in contraposition to older models at 8 MHz), the pinout seems to be largely the same in all three versions. 
  
 ^ KX-TD1232CE/1232BX etc.               ^ KX-TD816E (UK)                      ^ KX-TA1232                                                                     ^ ^ KX-TD1232CE/1232BX etc.               ^ KX-TD816E (UK)                      ^ KX-TA1232                                                                     ^
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 This PABX is, in fact, a simple, embedded m68k computer. Memory and peripherals are addressed directly, there's no MMU. Also, albeit the system has a 16-bit wide bus, it looks like only the memory chips are using all those lines (see diagram below.) All other devices I saw were using only eight lines of the data bus. Addressing lines seems also to go under-used for most devices, e.g. expansion cards using A1-A5, or even the Caller ID card, using A1 and A5, ignoring all others.  This PABX is, in fact, a simple, embedded m68k computer. Memory and peripherals are addressed directly, there's no MMU. Also, albeit the system has a 16-bit wide bus, it looks like only the memory chips are using all those lines (see diagram below.) All other devices I saw were using only eight lines of the data bus. Addressing lines seems also to go under-used for most devices, e.g. expansion cards using A1-A5, or even the Caller ID card, using A1 and A5, ignoring all others. 
 +
 +===== Memory =====
  
 {{ :telephony:rom_ram_rtc_td1232ce.png?600 |}} {{ :telephony:rom_ram_rtc_td1232ce.png?600 |}}
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 +{{ :telephony:ram_not_mounted_ta1232.png?400|}}
 +Those systems seem to be typically equipped with four RAM and two ROM chips. TA1232's Service Manual seems to suggest they might not be always populated. On my TD816BX, [[telephony:td816bx_hardware|they are]]. Since this is a purpose built embedded computer, rather than a general computer, we got SRAM chips soldered to exactly the number of lines they need, without room for larger chips. 
 +
 +I couldn't ascertain why the heck we have two small 32K chips as the first two SRAM IC's, although I find quite interesting the fact that the configuration dump does result in a file that's approximately 64 KB in size, and I remember reading somewhere that those systems hold the configuration in the SRAM's. How this is holding up after all those years scapes me, but the battery I thought to be specific to the RTC may have something to do with this.   
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 ===== Caller Identification Card ===== ===== Caller Identification Card =====
telephony/ta1232_td816_td1232_hw_arch.1745114611.txt.gz · Last modified: 2025/04/19 23:03 by prppedro

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