PIC16F724

Support summary

• Programming - NSDSP-1 with NSHVX or NSDSP-2
• Debugging provisions - No

ICSP Connection

All VSS and VDD pins must be connected. Even if one of these pins is not connected, programming may fail.

PIC16F724 can only be programmed with HVP (High Voltage Programming). This means it requires Vpp voltage (higher than Vdd) for programming.

NSDSP-2 generates Vpp internally and can program PIC16F724.

NSDSP-1 cannot generate Vpp. Therefore, to be programmed with NSDSP-1, PIC16F724 requires NSHVX High Voltage Extension or an external HVP circuit.

Target Voltage Below 2.7V

If voltage is less than 2.7V programming is severely limited - it is impossible to bulk erase the device, it is also impossible to erase configuration bits.

NSDSP-1 cannot detect target voltage and it assumes that the voltage is above 2.7V. If the actual target voltage is less, programming will fail. However, if you tell NSDSP that the target voltage is below 2.7V through programming software, NSDSP will use special low-voltage algorithm. NSDSP will verifies if the desired programming can be performed at voltages below 2.7V, and if it is possible (device is not code protected, configuration bits do not change or only change from 1 to 0), it performs the programming. If such programming is impossible, NSDSP software will stop and show an error message.

NSDSP-2 can detect actual voltage, therefore it may choose the algorithm based on the detected voltage. However, you can override this decision by specifying your own voltage value. This will disable the voltage detection. For example, you can try to force normal algorithm even if voltage is slightly less than the threashold.

Programming using low-voltage algorithm may be considerably slower. In addition, you may need to decrease programming speed to 3MHz or below.

Debugging

NSDSP cannot be used to debug PIC16F724.

Links

Microchip PIC16F724 page