Altera Mini USB Blaster Revision C Clone using the PIC18F14K50 - Page 1
Forum section: electronics / projects

author: Syntax Error
author_rank: Frequent Contributor
timestamp: July 15, 2020, 05:07:10 pm
content: "Altera Mini USB Blaster Revision C Clone using the PIC18F14K50"I have one of these dirt cheapAlteraMini USB Blaster clone dongle things. You know, the ones that spam ebay and ali-express when you search for a "JTAG programmer". So I wondered what exactly is inside?There are a few implementations that go inside these identical "revision C" boxes; a popular type uses STM chips, others use some indeterminate DIP packaged micro-controller. This incarnation uses the PIC18F14K50 with a LVC244A level shifter. That's pretty much it. No voltage regulators, no fancy blocking diodes, no flux capacitors... nada. So that's why it's really cheap huh? Just afancy12MHz crystal. Searching the interweb, I was unable to locate any information about this specific clone. Other than, these dongles work really slow and won't reliably connect. Note the ALTERA logo on the PCB? Altera/Intel it is not.In theory, the PIC18F14K50 provides the USB connection and decodes the Altera protocol. This cloneaquiresthe Altera USB vendor (0x09FB) and product (0x6001) ids. The LVC244A is a 5 volt tollerant level shifter that connects direct to the target equipment via the 2x5 10pin connector (J1). Power to the LVC244A is provided via pin 4 of J1 by the target equipment, designated astarget voltageTGRT (VCC). This maintains the correct voltage level on the target equipment side.In theory.The official (expensive) Altera USB Blaster Cable configures the connector pins in three operating modes; AS, PS and JTAG. I have no idea if this clone fully supports these. There is also a five holefeature connectorwhich is likely used for flashing the PIC in some anonymous Chinese factory/garage/dunny. If anyone knows of a of repo that has the firmware for this device, then please link-in below. Thanks.After a bit of lock downtrack-n-trace, I sketched up the schematic for this mystery device. If you're tearing down one of these clones, tearing out your hair trying to figure out what's inside, or just came across this post, greetings from theEEVBlog Forum.

author: oPossum
author_rank: Super Contributor
timestamp: July 15, 2020, 06:38:40 pm
content: Source and hex for the PIC:http://sa89a.net/ele/ub.htmDon't know if that is what is being used in the ebay/ali versions.

author: harerod
author_rank: Frequent Contributor
timestamp: March 26, 2021, 01:05:06 pm
content: TO referenced this post herehttps://www.eevblog.com/forum/microcontrollers/what-should-i-buy-to-start-learning-jtag-debugg/msg3530390/#msg3530390Syntax Error, could you check the actual resistor values for me? 100k seems awful high and my watery eye seems to spy a 101 marking on e.g. R12. That would most likely mean 100R (R as in Ohm).Much obliged.By the way - that is a fancy design. Back in the day we used to sodder an HC244 to some poor LPT1. Then along came that Windows 2000 or whatever and messed up direct hardware access.

author: Syntax Error
author_rank: Frequent Contributor
timestamp: March 26, 2021, 08:44:17 pm
content: I can confirm those resistor values are 100R (SMD=101)