Products > Test Equipment
open source GPIB adapter
Kean:
Almost 15k pcs (TQFP) expected to be available for direct purchase in March (I don't put much trust in their stock levels or ETA dates though)
https://www.microchipdirect.com/product/ATMEGA32U4-AUR
dorkshoei:
--- Quote from: dorkshoei on November 30, 2021, 02:49:20 am ---
--- Quote from: Nx-1997 on November 26, 2021, 01:14:01 am ---
For xyphro’s UsbGpib:
ATMEGA32U4RC-AU-ND 5pcs – $37.65 CAD Digikey
--- End quote ---
ATMEGA32U4 seems pretty solidly discontinued. Octopart shows 0 in stock at authorized distributors.
Utsource.com who are IME about as reputable as you can get with Chinese chip sellers shows their stock is all "used". All the third parties on their site claim new which I assume is BS along with theChinese eBay/aliexpress sellers.
--- End quote ---
I'm also pretty sure ATMEGA32U4RC above is not the correct part. Looking at the data sheet the RC has an internal oscillator and isn't compatible with an external. The UsbGpib uses an external 16mhz crystal.
You need the ATMEGA32U4-AU which of course is not in stock. I may get used ones from utsource, I've had fairly good luck with them before.
maxwell3e10:
I am wondering if the xyphro's code can be modified slightly to use standard Arduino Pro Micro. A few of the pin assignments need to be changed and the bootloader is different. But otherwise one can just get a complete Arduino board and wire it up to GPIB connector.
Nx-1997:
--- Quote from: dorkshoei on November 30, 2021, 03:29:48 pm ---
--- Quote from: dorkshoei on November 30, 2021, 02:49:20 am ---
--- Quote from: Nx-1997 on November 26, 2021, 01:14:01 am ---
For xyphro’s UsbGpib:
ATMEGA32U4RC-AU-ND 5pcs – $37.65 CAD Digikey
--- End quote ---
ATMEGA32U4 seems pretty solidly discontinued. Octopart shows 0 in stock at authorized distributors.
Utsource.com who are IME about as reputable as you can get with Chinese chip sellers shows their stock is all "used". All the third parties on their site claim new which I assume is BS along with theChinese eBay/aliexpress sellers.
--- End quote ---
I'm also pretty sure ATMEGA32U4RC above is not the correct part. Looking at the data sheet the RC has an internal oscillator and isn't compatible with an external. The UsbGpib uses an external 16mhz crystal.
You need the ATMEGA32U4-AU which of course is not in stock. I may get used ones from utsource, I've had fairly good luck with them before.
--- End quote ---
The ATMEGA32U4RC and ATMEGA32U4 are the same, only difference is the fuse configuration. I bought the ATMEGA32U4RC because the ATMEGA32U4 was out of stock. You will have to set the fuses anyway when flashing the bootloader.
dorkshoei:
--- Quote from: Nx-1997 on November 30, 2021, 06:26:24 pm ---
The ATMEGA32U4RC and ATMEGA32U4 are the same, only difference is the fuse configuration. I bought the ATMEGA32U4RC because the ATMEGA32U4 was out of stock. You will have to set the fuses anyway when flashing the bootloader.
--- End quote ---
Perhaps I'm just not understanding the datasheet or it's confusingly worded.
6.2.1 Default Clock Source ATmega16U4 and ATmega32U4 The device is shipped with Low Power Crystal Oscillator (8.0MHz-16MHz) enabled and with the fuse CKDIV8 programmed, resulting in 1.0MHz system clock with an 8 MHz crystal. See Table 28-5 on page 348 for an overview of the default Clock Selection Fuse setting.
6.2.2 Default Clock Source ATmega16U4RC and ATmega32U4RC The device is shipped with Calibrated Internal RC oscillator (8.0MHz) enabled and with the fuse CKDIV8 programmed, resulting in 1.0MHz system clock. See Table 28-5 on page 348 for an overview of the default Clock Selection Fuse setting.
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