AN977 Datasheet, PDF (2/17 Pages) STMicroelectronics – GUIDELINES FOR UPGRADING FROM THE ST92F120

GUIDELINES FOR UPGRADING FROM THE ST92F120 (0.50 µm) TO THE ST92F124...
1 UPGRADING FROM THE ST92F120 TO THE ST92F124/F150/F250
ST92F124/F150/F250 microcontrollers using 0.35 micron technology are similar to ST92F120
microcontrollers using 0.50 micron technology, but shrinking is used to add some new fea-
tures and to improve the performances of ST92F124/F150/F250 devices. Almost all periph-
erals keep the same features, which is why this document focuses only on the modified sec-
tions. If there is no difference between the 0.50 micron peripheral compared to the 0.35 one,
other than its technology and design methodology, the peripheral is not presented. The new
analog to digital converter (ADC) is the major change. This ADC uses a single 16 channel A/
D converter with 10 bits resolution instead of two 8-channel A/D converters with 8-bit resolu-
tion. The new memory organization, new reset and clock control unit, internal voltage regula-
tors and new I/O buffers will almost be transparent changes for the application. The new pe-
ripherals are the Controller Area Network (CAN) and the asynchronous Serial Communication
Interface (SCI-A).
1.1 PINOUT
The ST92F124/F150/F250 was designed in order to be able to replace the ST92F120. Thus,
pinouts are nearly the same. The few differences are described below:
– Clock2 was remapped from port P9.6 to P4.1
– Analog input channels were remapped according to the table below.
Table 1. Analog Input Channel Mapping
PIN
P8.7
...
ST92F120 Pinout
A1IN0
...
ST92F124/F150/F250 Pinout
AIN7
...
P8.0
P7.7
...
P7.0
A1IN7
A0IN7
...
A0IN0
AIN0
AIN15
...
AIN8
– RXCLK1(P9.3), TXCLK1/ CLKOUT1 (P9.2), DCD1 (P9.3), RTS1 (P9.5) were removed be-
cause SCI1 was replaced by SCI-A.
– A21(P9.7) down to A16 (P9.2) were added in order to be able to address up to 22 bits exter-
nally.
– 2 new CAN peripheral devices are available: TX0 and RX0 (CAN0) on ports P5.0 and P5.1
and TX1 and RX1 (CAN1) on dedicated pins.
1.2 RW RESET STATE
Under Reset state, RW is held high with an internal weak pull-up whereas it was not on the
ST92F120.
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