Many downplay the importance of 8-bit microcontrollers given the latest crop of 32-bit micros but developers know that choosing the right microcontroller for the job is more important than using a 32-bit C compiler. Freescale has been delivering a range of microcontrollers including its 8-bit family. The latest 5V part is the SO8P line that delivers the needed performance and reliability for harsh environments. Low voltage parts will find it hard to keep up in these environment.
Freescale actually has two new lines. The 10 MHz S08P (Fig. 1) and the 20 MHz S08RN. The latter is AEC-Q100-compliant and qualified up to 125°C. It targets the automotive space. The S08P MCU family targets the industrial and white goods market.
Both new families are 5V parts with a pair of true open drain outputs. They also have more RAM reflecting the move to more advanced programs and the use of C for coding. The chips have a unique ID capability for identification purpose. They also have a 16-channel, 12-bit SAR ADC with dedicated FIFOs to reduce processor overhead.
The 20 MHz S08P MCU family includes three classes of devices, the PT, PA and PL. They are compliant with the IEC-60730 safety standard for household appliances. The PT (and RT) parts including a T in their name to designate touch sensing support. This is a hardware touch sensing interface (TSI), not a software-only solution. It handles up to 16 channels and it supports interfaces such as sliders and knobs. The chips include EEPROM for parameter storage.
Many of the applications address motor control. Freescale's FlexTimer support allows an 8-bit micro to handle BLDC motors. The I/O has high drive capability and there are the two open drain pins as well. The chip has new power/ground layout and new packaging to deliver better EFT/EMI support. The chips are pin compatible.
The chips are available in 64-QFP and 64-LQFP packages. Pricing starts at $0.35 for the 8-pin/2K Flash (S08PL2) part. The minimum availability is 10 years with 15 for the automotive parts.
The development kits take advantage of Freescale's Tower development system/ The TWR-S08PT60 (Fig. 2) and S08RT version area available with software support via Freescale's Code Warrior with a 60K code size limit. Third party support includes packages like IAR's Embedded Workbench.
Overall, Freescale has delivered the chips and tools needed to handle rugged industrial, consumer and automotive applications using low cost 8-bit micros.