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ISP over SOIC Clip
Posted: Fri Mar 04, 2016 8:02 am
by woko
Dear Reveltronics Team,
if we plan to use the SOIC clip for programming what do we have to consider in the PCB design?
Can we connect the WP and HOLD pins on the EEPROM (N25Q128A) direct to VCC or GND?
Best regards,
Wolfgang
Re: ISP over SOIC Clip
Posted: Fri Mar 04, 2016 5:58 pm
by ArT
N25Q128A is not EEPROM, it is FLASH SPI.
It is hard to make lecture from design rules in single post, but in general:
- SPI wires designed with SPI standard (e.g. pullups 4.7k - 10k, CS pin decoupled <100n, power supply decoupled etc.)
- WP and HOLD connected to VCC or with pull-up >10k to VCC or pull-down to GND
- master device for SPI bus should be in reset state during flash programming
- all other slaves should be in not active mode (CS high)
- short wires without any additional elements
- it may be also necessary to adjust impedance for SPI bus for higher freq.
- external power supply if current exceed >100mA
Hope it helps.
Re: ISP over SOIC Clip
Posted: Thu Mar 10, 2016 2:01 pm
by woko
thanks for the answer. What happens if HOLD or WP are hardwired to GND or VCC?
Will it just not work or can board or programmer be damaged?
Re: ISP over SOIC Clip
Posted: Thu Mar 10, 2016 2:05 pm
by ArT
- if WP or HOLD are hardwired to VCC - nothing will happen - it should work
- if WP or HOLD are hardwired to GND - it will be short circuit during programming:
- in programming with programmer power supply (VPP ON) it will give overload protection error,
- in programming with external power supply (and VPP OFF) there is risk of damage - if WP or HOLD are pulled-down to GND or pulled-up to VCC e.g. with 10k resistor - nothing will happen - it should work
Re: ISP over SOIC Clip
Posted: Thu Mar 10, 2016 2:46 pm
by woko
great, thats all I need to know. Thanks!