kawk
Junior Member level 2
altera bitblaster protocol
I've received some mails from others who used my logic with varying success. Following are some general tips.
The ZIP on my site doesn't yet contain the updates that make AS mode work. Please manually integrate the code from my previous postings here (until I find time to make a new "release").
If it works "partially" for you, "sometimes" or "it programs the device, but the device doesn't work afterwards", your setup maybe isn't suitable for clear transmission of signals at several MHz. It may still be a critical timing in the logic, but I'm using it even slightly "overclocked" at 25 MHz and haven't had any errors since months. So I doubt it's the logic.
Try reducing the clock to the CPLD from 24 MHz to, say, 6 MHz.
Whenever I experienced problems, it was due to wrong connections, bad pullup/pulldown resistors on the target JTAG interface, or mismatch between logic levels (3.3/5 V) of Blaster vs. target JTAG interface.
For example, we once had (with a Cyclone device) 10 kOhm pullups on TDI and TMS and 10 kOhm pulldown on TCK, and experienced some problems, but they were solved after we learned that TCK pulldown should be 1 kOhm.
For the CPLD variant I actually used a EPM7064SLC44-10, because I needed 5V logic interface. If you want to attach your cable directly to a device with 3.3V logic you should another CPLD, or, as Altera does it, a level translator/driver between the devices.
The cable between CPLD to target should not exceed 10 cm in length.
Kolja
I've received some mails from others who used my logic with varying success. Following are some general tips.
The ZIP on my site doesn't yet contain the updates that make AS mode work. Please manually integrate the code from my previous postings here (until I find time to make a new "release").
If it works "partially" for you, "sometimes" or "it programs the device, but the device doesn't work afterwards", your setup maybe isn't suitable for clear transmission of signals at several MHz. It may still be a critical timing in the logic, but I'm using it even slightly "overclocked" at 25 MHz and haven't had any errors since months. So I doubt it's the logic.
Try reducing the clock to the CPLD from 24 MHz to, say, 6 MHz.
Whenever I experienced problems, it was due to wrong connections, bad pullup/pulldown resistors on the target JTAG interface, or mismatch between logic levels (3.3/5 V) of Blaster vs. target JTAG interface.
For example, we once had (with a Cyclone device) 10 kOhm pullups on TDI and TMS and 10 kOhm pulldown on TCK, and experienced some problems, but they were solved after we learned that TCK pulldown should be 1 kOhm.
For the CPLD variant I actually used a EPM7064SLC44-10, because I needed 5V logic interface. If you want to attach your cable directly to a device with 3.3V logic you should another CPLD, or, as Altera does it, a level translator/driver between the devices.
The cable between CPLD to target should not exceed 10 cm in length.
Kolja