Where The Constants Live
The PIC16F723 is the 4K-word, 192-byte-SRAM member of the 28-pin 72x group, and like every part in this family it has no data EEPROM and no HEF block. That fact shapes recovery expectations more than anything else: there is exactly one nonvolatile region, the 0x0000-0x0FFF program array, and everything the application remembers between power cycles was stored inside it. Tables, calibration records, serialized identifiers – all of it decodes as ordinary program memory words.
Same Lock, Same Sweep
Protection remains the single CP bit in the configuration word at 0x2007. With the bit set, the array reads back as 0x000 through ICSP while the ID word at 0x2006 stays open. The distinguishing skill on this family is boundary control: 0x07FF is the end of a 722, 0x0FFF the end of a 723, and 0x1FFF the end of an 8K PIC16F726. A reader set to the wrong boundary produces a phantom protected region that has fooled more than one in-house attempt.
The Peripheral Set In The Image
A 723 image typically shows:
– Two CCP modules configured for PWM or capture against Timer1/Timer2. – An AUSART initialized for 9600 or 19200 baud from the 16 MHz internal clock. – SSP code in SPI mode 0 or I2C slave mode with address masking. – mTouch sensing loops across the CPS channels.
Because the converter is eight-bit on the whole family, ADC results occupy single registers and the sampling loops are compact – one of the fastest visual checks that a recovered image belongs to this group rather than a 10-bit sibling.
The VCAP Detail
Members of the 72x family with the on-chip 3.2 V regulator (722, 723, 724, 726, 727) expose a VCAP pin that must sit at the right impedance for the core to run. During on-board recovery the regulator is normally left powered so the ICSP interface works as production intended; the capacitor specification matters if the board has been in the field for years and the MLCC has drifted.
What The Client Receives
The deliverable set for a 723 job: the HEX file, an instruction-level disassembly with the CCP and AUSART blocks commented, a configuration-word report, and a checksum tying the image to the physical part. If the application was built with a compiler that emits recognizable library signatures – delay tables, BCD conversion routines – those are labeled in the listing.
Four Thousand Words And Eleven Channels
The PIC16F723 is a 28-pin member of the 72x line: 4,096 words of flash, 192 bytes of SRAM, 25 I/O pins, eleven ten-bit ADC channels, two ECCP and one CCP, one EUSART and one MSSP. There is no data EEPROM, so any stored parameter is in flash. The core is the classic mid-range one with thirty-five instructions rather than the enhanced set.
Mid-Range Code Reads Differently
The older instruction set has no automatic context save and a shallower stack, so firmware written for it is explicit about saving state and tends to use fewer subroutine levels. In the disassembly that shows as long linear blocks with hand-written save and restore sequences, and a reviewer used to enhanced mid-range code has to adjust: there are no MOVLP-style bank selects, and the banking is done by hand.
– Flash: 0x0000-0x0FFF (4K words), 0x3FFF erased, 0x0000 protected. – Configuration: 0x2007, device ID 0x2006.
What A 72x Image Contains
These parts predate the configurable logic and analog blocks, so the image is peripheral setup plus application. The ADC is eight-bit on this line rather than ten, which matters when a client compares a recovered table against measurements taken on a modern part – the quantisation is coarser and the constants reflect that.
Deliverables
HEX at word addresses, annotated disassembly with the bank-switch sequences resolved, configuration report, checksum tied to the die. Protection as found.
The 723 is a routine recovery: two-wire ICSP, no decapsulation, part returned to service. For the 36-pin-rich members like the PIC16F724, the procedure is identical with 14 converter channels instead of 11. Start a 723 recovery by writing to the service desk or the contact form with the part number, package code and any surviving build artifacts.