view tcsm2-notes/trco @ 20:7cd046ffefe7

gsmx2tsrc: print input frame number comments on separate lines
author Mychaela Falconia <falcon@freecalypso.org>
date Sun, 23 Jun 2024 22:04:08 +0000
parents b36419bbc2c4
children
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Major components on TRCO board:

1x Lattice ispLSI1032E PLD, same as on TR16-S
1x CPU: Intel TN80C186EB20

Big oscillator, markings on the metal can package:

	DFA 36-TR
	16.384 MHz
	A36060 0049

Close to it there is a MAS9316N DAC - thus the big oscillator is likely the
system-wide TDM clock (the one that can be synced to various inputs), and the
DAC is for control loop adjustments aiming to lock this oscillator to the
selected external clock source.  Based on the size of the can, I originally
thought it was an OCXO, but when I searched for "DFA 36-TR", the hits I got
(only sellers, no datasheet) say TCXO.  Who knows...

3x Infineon chips, 2x SAB 82525 (2x HDLC) and 1x SAB 82526 (1x HDLC):
the 5 HDLC channels which the available documentation touches on.

8x PLCC32 chips (9 pins on wide side, 7 pins on narrow side) with stickers
on them that obscure the markings underneath.  The markings read IC45 through
IC48 in the top row of 4, IC55 through IC58 in the bottom row of 4.  All 8
ICs are directly soldered.  Suspected flash memory.

Update with IC55 sticker peeled off: the IC underneath is AM29F010B-120JC,
just like I suspected.  Interestingly, it also says "(C) 1998 AMD" - the year
is slightly newer than my original assumptions of 1996 vintage.

Next to these 8 ICs there is a socketed PLCC44 IC (11 pins on each side)
with a sticker that reads:

	TRCO
	6.1-0
	TC1ROMQL

It is clearly a programmed part of some kind, but not clear if it is flash
(boot code?) or some PLD or whatever.

Update after peeling off the sticker: the part is ST M27C4002, an OTP ROM!
It is clearly the boot PROM, whereas the other 8 ICs (all 29F010?) are the
flash memory array.  The large size of both the flash array and the boot PROM
is surprising:

* The boot PROM is 4 Mbit (256K x 16) - that's 512 KiB, half of 80186 address
  space if fully and directly mapped.

* Assuming that the 8 bit wide 29F010 chips are wired in pairs across the
  16 bit wide data bus, we got 1 MiB in total, in 4 banks of 256 KiB each.
  More than 80186 can address directly - is it a bank-switched memory system?

RAM chips:

* 2x Samsung K6T1008C2E-GL70.  Each of these ICs is 128K x 8 static RAM;
  the design probably uses two of them across the 16 bit wide data bus.
  256 KiB of RAM here.

* 1x CY62256-70SNC - 32K x 8 (256 Kbit) static RAM.  What is it for???