RX24U is the branch of the RX24 family that moved the analog front end onto the die. R5F524UBAGFP carries differential programmable gain amplifiers, a twenty-channel 12-bit converter and two 8-bit DACs next to the same RXv2 core, 256 KB of flash and 32 KB of RAM as its RX24T cousins – and it is rated to 105°C rather than 85°C. Boards built around it have fewer external parts than an equivalent RX24T design, which is exactly why the firmware is harder to reconstruct from the schematic alone.
What The Integration Changes
When the amplifier is external, the gain is a resistor ratio and the schematic tells you what the firmware assumes. When the amplifier is inside the MCU, the gain is a register value written by the start-up code. Pull the code out and the gain setting comes with it; lose the code and there is nothing on the board to measure.
That is the practical argument for a full read on this part, including the option bytes and, where possible, a live register capture.
Memory And Peripherals
| Item | Value |
|---|---|
| ROM | 256 KB, FFFC0000h upward |
| RAM | 32 KB |
| E2 data flash | 8 KB |
| ADC | 12-bit, 20 channels |
| DAC | 2 channels, 8-bit |
| I/O | 79 pins |
| Temperature | -40 to 105°C |
The 105°C rating is unusual in this group and it changes intake handling: these boards are often mounted on a heatsink with thermal compound, and the compound has to be preserved so the unit can be re-qualified after a read.
Protection And The Read
ID code protection gates boot-mode SCI and the debugging emulator; ROM code protection is a block 0 value that disables parallel-programmer reads; start-up program protection and area protection govern self-programming. None of them erase the array. The read covers code from FFFC0000h, the E2 area separately, the option bytes, and the 16-byte ID code structure at FFFFFFA0h.
Why A Differential Front End Matters To A Copy
Two motors driven from one die means two current-sense paths, each with its own offset and gain. The calibration for both normally lives in E2 data flash, written at end of line. A code-only dump leaves the customer with firmware that runs and a drive that measures current wrong. Reading the E2 area is not an optional extra on this part; it is half the product.
Deliverables
Intel HEX, E2 binary with the calibration block identified, option bytes, block map, ID code page, and – if the unit powered up – a record of the PGA gain settings, ADC sequencing and DAC output values at idle.
Two Current Sense Paths, Two Calibrations
A dual-motor RX24U design has two shunt or two flux-gate paths, each with its own offset and gain, and each calibrated at end of line. The calibration values live in E2 data flash, and they are specific to the board – not to the firmware, not to the motor.
That is the single strongest argument for reading the E2 area on this part. A replacement programmed with code alone will run, measure current with the wrong gain, and either trip early or fail to trip at all. Neither symptom looks like a firmware problem, which is why it takes a long time to diagnose.
Why 105°C Changes The Intake
A 105°C rating puts this part in a gap between consumer and automotive: hot enough that the board is mounted for thermal reasons, not hot enough that the assembly is sealed. Units arrive on heatsinks with compound, sometimes with a fan, occasionally with a thermal pad that has degraded.
The compound is left alone. Where a read requires removing the board from the heatsink, the compound is photographed and described, and the customer is told what will be needed to re-mount it. On a drive that is still in production, that detail is worth more than the hex file.
Intake
Keep the thermal interface material intact. Note the bus voltage, the number of motors, and the maximum ambient the product sees. If the unit is dead, say whether it failed hot or cold, since that decides whether the E2 area is worth reading twice.
Start with the services page or the contact form. The RX24T counterpart with the same array is R5F524TAADFP, and the 384 KB RX24T device is R5F524TCADFP.