The Renesas RX23E-B is the second RX family member that's made for precision analogue designs. The digital part is a fairly small microcontroller. Renesas' own RX core. The analogue part is why you 'd select this device. It has most of the things used to make sensitive sensor measurements:
- 24 bit delta-sigma ADC, with a
- programmable gain amplifier (x1 - x128)
- 5 V (and on some devices 10 V) analogue inputs
and a set of modules to assist with measuring signals:
- a multiplexer that can switch 6 differential signals or 16 single ones
- voltage reference
- BIAS voltage generator
- current sources for excitation
- 16-bit DAC, with buffer
- an additional, faster, 12-bit 8 channel ADC
- a low side switch, 10 Ohm on-resistance, max 30 mA.
- temperature sensor, and
- (absence of) voltage detectors
image source: product page
These blocks are register-controlled. Parts can be bypassed or switched off if not needed. For sensitive measurements, e.g.: like load cells (and other bridge type setups), thermocouples, the IC can provide the signals to bias / excite the circuit. The reference signals can be routed to the ADCs.
I'm working on a PCB for the controller. My goal is to get all of the analogue related functionality broken out. And create a development kit.
My original goals were simpler: I wanted to use the smallest of packages, and create a decent load cell design. But no vendor has the low-pin-count packages in stock (at the time of writing). The only one on stock is the biggest of the family.100 pins, full option. My board will exploit most of that version's capabilities. Whatever I manage to fit in.
image: user manual
