USB At 44 Pins
The PIC18F44J50 pairs the USB module with the wide package: 16 KB of program memory (0x0000-0x3FFF), 3,776 bytes of SRAM, twenty-two remappable I/O lines, thirteen channels of ten-bit ADC, a PMP parallel port, full-speed USB 2.0, 48 MHz core, Deep Sleep, PPS, RTCC, CTMU, two ECCP modules, two EUSARTs, two MSSPs, two comparators – no EEPROM, 2.0-3.6 V. USB instruments with parallel attached front ends choose this die.
Lock And Sweep
PIC18 configuration at 0x300000 with CP0/CP1 and WRT bits; ID at 0x3FFFFE. Sweep:
– Array: 0x0000-0x3FFF, 0x0000 under CP. – Configuration: 0x300000 window. – ID: 0x3FFFFE-0x3FFFFF.
The 16 KB boundary separates the 44J50 from the 32 KB PIC18F45J50 and 64 KB PIC18F46J50 in the same package.
Image Anatomy
The USB stack dominates as on the 28-pin members – descriptor tables with ASCII strings, endpoint logic, buffer descriptors in the dual-access RAM. The parallel-port setup marks PMP-based boards; the RTCC scheduler and emulated-EEPROM parameter blocks near the array top complete the picture.
The Session
The 44-pin body carries both a USB controller and a parallel master port, and both consume pins that a programmer also needs; the session therefore confirms which pads are free before applying power. Reading follows the erase-block grid rather than a raw byte stream, so the resulting image can be patched block by block later without disturbing the descriptor region.
Deliverables
HEX file, annotated disassembly with the USB, parallel and parameter regions labeled, configuration report, checksum tied to the die.
The 44-Pin USB Body
Sixteen kilobytes on this die arrives in 1 KB erase blocks, and that granularity is worth stating because it sets what a partial rebuild can preserve. A client who only needs the USB descriptor block changed can be given a block-aligned patch rather than a full image, and the report marks which block holds the descriptors so the patch lands cleanly. That is a smaller job than a full port and it keeps the rest of the original build intact.
Where Sixteen Kilobytes Goes
Roughly the first quarter of the array is the USB stack and descriptor set, and the rest is the translation layer. That ratio makes the disassembly easy to read: the descriptor block is a short run of tables immediately after the vectors, the endpoint handlers follow, and the application occupies the top half with its own dispatch table. On a design that also uses the parallel port, the PMP driver sits between the two and shows as the dense store loop described on the PIC18F44J10 page.
– Array: 0x0000-0x3FFF, 0x3FFF erased, 0x0000 under protection. – Configuration: 0x300000-0x300007. – ID: 0x3FFFFE-0x3FFFFF.
The Protect Bits Are Part Of The Answer
Reading the configuration window is not a formality on this part. The write-protect bits over the low block tell the operator whether the factory bootloader was protected, and the code-protect bit tells them whether the protection was applied at programming time or later. Clients who inherited a product without documentation use this to work out how the original contract manufacturer was instructed, which is often the difference between rebuilding the firmware and rebuilding the whole production process.
Limits Of A 16 KB Image
There is no room for a bootloader, an application and a parameter store in 16 KB, so something has to give. Most designs drop the parameter store and keep constants in flash; the recovered image then shows a long table of floats or fixed-point values near the top of the array with no code referencing them directly – the references are computed at run time. Those tables are labelled in the report but not interpreted, because interpreting them requires the sensor datasheet the client usually still has.
Handover Package
HEX at word addresses, annotated disassembly with the USB stack and the translation layer separated, configuration report, checksum tied to the die, protection left as found.
To extract a locked 44J50, use the services desk or the contact form.