List of components for the HRPT/PDUS decoder.

(I have to re-check this, to make sure everything is OK.)

Component Value/type Quantity Schematic name Comments
Integrated circuits. XC3042-70PC84 or equivalent 2 IC1, IC4 Fab.: Xilinx, Lucent (former AT&T).
514256 or equivalent 1 IC5 dynamic RAM,
256k words / 4 bits
27(C)512 or 27(C)256 1 IC2 4 programs fit in 256
74HCT14 1 IC3, IC6
Sockets. PLCC 84 pin 2 for IC11, IC4
DIL 28 pins 1 for IC2
DIL 20 pins 1 for IC5 optional
DIL 14 pins 1 for IC3, IC6 optional
Diodes. BB109, BB809 etc. 1 D1 Any varicap of ~30pF at 3V and ~6pF at 25V should do
1N4148 etc. 9 D2-D10
Dual LED 1 SYNC
Single LEDs 8 ERR, ALARM, 6x CHANNEL
Xtal. 4.433619 MHz 1 X1 any value between 4 and 6 MHz is OK
See extra info.
Coil. 12 uH 1 L1
Capacitors 27 pF 1 C1
4p-30 pF trimmer 1 C2
330 pF 1 C3
100 nF 2 C4, C8
10 pF 2 C5, C6
10 uF 1 C7
0.1 uF 3 C8, C9, C10
1 nF 1 C11
Resistors 1M 2 R1, R9
220 2 R2, R10
4k7 2 R3, R7
100 1 R4
100k 2 R5, R6
10k 1 R8
100 1 R14
820 10 RL
10k 3 R11, R12, R13
10k array of 8 1 RS 6 elements used
100 1 R14


Xtal frequency.

For HRPT/HRI the xtal frequency should be at least 3 MHz.
For CHRPT, to record all 10 channels, a value of at least 6 MHz is needed. Succesfull recording of all 10 channels also depends on the parallel port; some ports are reported to be too slow, with others recording of all 10 channels is no problem. This is something you have to try.
The maximum XTAL frequency depends on the toggle frequency of the used FPGA. Unfortunately, I can't reproduce the exact numbers; next are guaranteed. These numbers are worst case (slow device, high temperature); in most cases a higher frequency is possible. (If you have a 50 MHz device, just try a 6 MHz xtal, and check with the CHRPT generator if you get a perfect test image.)

Alternatives for 514256 DRAM
Organization/
Density
Fujitsu
MB
Goldstar
GM
Hitachi
HM
Hyundai
HY
Micron
MT
Mitsubishi
M5M
256kx4 (1M) 81C4256 71C4256 514256 534256 4C4256 44256
Organization/
Density
Motorola
MCM
NEC
UPD
Oki
MSM
Samsung
KM
Texas Inst.
TI
Toshiba
TC
256kx4 (1M) 514256 424256 514256 44C256 44C256 514256