PIC16F627

Support summary

• Programming - Yes
• Debugging provisions - No

LVP Programming

Low-Voltage Programming (LVP) can only be used for these PIC devices if the LVP configuration bit is enabled. Fresh (unprogrammed) devices have LVP bit set and therefore they can be programmed. It is impossible to disable LVP bit during LVP programming, but if the device has been previously programmed with HVP programmer, the LVP bit may have been disabled.

When brown-out is enabled with BOREN configuration bit, LVP is only possible when the VDD voltage is above the brown-out threshold.

These limitations may be avoided with High-Voltage Programming (HVP). NSDSP-2 can generate high voltage for HVP internally. NSDSP-1 cannot, therefore NSDSP-1 requires an external circuit for HVP.

HVP Programming

NSDSP-2 can generate 12 V voltage internally, and therefore can programPIC16F627 with HVP.

With NSDSP-1, HVP programming is possible, but only with an external HVP circuit.

NSHVX will not work with PIC16F627 because NSHVX produces 9 V high voltage, but this chip requires at least 11 V. If you need NSHVX version which produces 12 V and is suitable for this PIC, please contact us.

Microchip HVP programming specificatons for PIC16F627 require that VPP is applied to MCLR before VDD. Since NSDSP does not have any control of VDD, this requirement cannot be satisfied, however, in our tests the HVP programming has succeeded even without VDD manipulation. Therefore, NSDSP software, starting release 126, supports HVP programming for PIC16F627.

Be careful. It is possible to brick PIC16F627 with HVP programming if each of these three conditions is met:

• MCLRE and LVP configuration bits are disabled
• The PIC uses internal oscillator, or an external oscillator which is connected while the programming takes place
• RB6 or RB7 pin is driven or T1OSCEN is set within 20 ms from the reset

Target Voltage below 4.5V

If voltage is less than 4.5V it is impossible to bulk erase the device. Unless the PIC device is code protected, NSDSP still can program the device, however, without the bulk erase it takes longer.

NSDSP cannot detect target voltage and it assumes that the voltage is above 4.5V. This ensures fast programming at usual voltages. However, if you want to program at voltages below 4.5V, you must specify the actual target voltage through programming software, or the programming will fail. If you specify the voltage below 4.5V NSDSP will apply special programming algorithm, which does not use bulk erase, but is slower than the regular algorithm.

If you are programming a device which is code protected, NSDSP cannot remove protection if the voltage is below 4.5V.

When programming at voltages below 4.5V, NSDSP tries to save time, and therefore does not erase memory areas which are not being programmed. If such erasing is needed, you can erase the device manually before programming.

Programming Benchmarks

We have measured time necessary to program and verify PIC16F627.

The measurements reflect the time necessary to program/verify the entire chip, including all user programmable memory areas and very slow data EEPROM.

Debugging

NSDSP cannot be used to debug PIC16F627.

Links

Microchip PIC16F627 page