WP-34s from HP-30B: FTDI Board alternative FLASHing Instructions

[iceman]

See Attached photo. The FTDI BOARD can be obtained as eBay item

301380778878,
191362294962 or,
111514068357

Or just search eBay for "FTDI" then sort on "Price + Shipping: lowest first"

You may wish to perform a self test on the HP-30B PRIOR to FLASHING as there is no self test in WP-34s code.

================ HP-30B Self Test =========================

Press and hold: PMT
Press and release: ON
Release: PMT

Display "Tst Screen"
Press INPUT
Perform the screen test by pressing any key 12 times.
It should return to Display "Tst Screen"

Press the DOWN arrow then "INPUT" (or "ENTER" if you already re-labelled the key.)
Display "Tst Keyboard"
Press INPUT
Perform the keyboard test by pressing every key at least one time
Note the key number of each key on the display. (Not necessarily sequential, or contiguous.)
Press [ON/CE] key to exit test when prompt is "Tst Screen" or "Tst Keyboard"

===========HP-30B FLASHing Instructions=======================

1) FTDI-BOARD. IMPORTANT: Set jumper to 3.3V
2) LEFT [OPEN(DTR), RX, TX, +3V, OPEN(CTS), GND] RIGHT
3) Connect calculator as follows:

[RESET Button]
-----O

RX TX +3V
O---O---O

O---O---O
E GND RESET
R
A
S
E

FTDI TX -> 1KOHM -> CALCULATOR RX
FTDI RX <- 1KOHM <- CALCULATOR TX
FTDI +3V -> CALCULATOR +3V
FTDI GND -> CALCULATOR GND

4)Apply power (Tx and Rx do not need to be connected for this part)
5)Short and hold +3V and ERASE
6)Press the "ON" Key
7)Release short on +3V and ERASE
8)Short RESET and GND or press a Paper Clip in the RESET hole
9)Press the "ON" Key (no response, it is now brain-dead and waiting to be FLASHed)
10)Connect Tx and Rx (as well as +3V and GND)
11)Download Firmware using MySamba
12)Press RESET or remove Power
13)Apply Power and press "ON"
14) h 1 . ENTER (Crystal Test)
15) h 3 x ^ Enter (Stopwatch Test)

[Terje Vallestad]

Thanks iceman

Your clear instructions resulted in successful flashing at very low cost even though I had to buy all the components from scratch. Allows a nice sense of achievement when the calculator turns on in its new skin....

Thanks again, Terje

[iceman]

With pleasure Terje! I share your sense of satisfaction every time a new WP34S wakes up after FLASH. I should mention that I do not actually connect the power to the programming port. I use alligator clips to connect to the battery contacts. I hold the 1K resistors against the Tx and Rx contacts during FLASH (24 seconds). Seems to work fine.

I really have to admire the programming cable that Katie Wasserman designed - wow. I was going to build one. I even identified all the parts I would need to order from eBay, but it turns out that beryllium copper is hard to find in small quantities.

Also, see the wireless stuff Katie did in the same article. Again - wow

We all also owe a collective salute of appreciation to Eric Rechlin for producing such a high quality yet low priced overlay which I marvel at each time I apply the key pads with my tweezers under the magnifying lamp. By the way, if you have not caught it, his new video offers some invaluable tips.

[logicmonkey]

FTDI RX <- 1KOHM <- CALCULATOR TX

what is the reason for this? the calculator is at 3V0 and can't overdrive the FTDI device which is at 3V3

[jebem]

(01-05-2015 10:18 AM)logicmonkey Wrote:  FTDI RX <- 1KOHM <- CALCULATOR TX

what is the reason for this? the calculator is at 3V0 and can't overdrive the FTDI device which is at 3V3

The data lines will swing from +V to Zero when sending the encoded data bits.
The serial TTL interface depends on current flowing to transfer the encoded data bits.
So this is just a best practice commonly used in electronics and it acts as a current limiter.
And of course it is handy to use small value resistors instead of bare wires if you are using the proposed method of not using a dedicated POGO plug

I did it in this way until I feed up dealing with unstable wire connections and decided to build my own flash box serial cable, equipped with dedicated internal 3.3V power supply and press buttons switches for Reset and Erase.
http://www.hpmuseum.org/forum/thread-1083.html

[iceman]

The calculator is powered from the FTDI. No batteries present.

[John Galt]

(01-05-2015 06:56 AM)iceman Wrote:  I really have to admire the programming cable that Katie Wasserman designed - wow. I was going to build one. I even identified all the parts I would need to order from eBay, but it turns out that beryllium copper is hard to find in small quantities.

Also, see the wireless stuff Katie did in the same article. Again - wow

Agreed!

You don't really need BeCu though. The primary advantage to using BeCu is the ability to easily solder it, which will not be required if you build a connector / cable assembly with spring pins similar to the one jebem and Dave Frederickson built. You can use any reasonably thin, springy metal.

Refer to the thread he linked, or to mine here. The spring pins and connectors required are explained there.