MC9S12A256 Motorola, MC9S12A256 Datasheet - Page 59

• Manufacturer Part Number: MC9S12A256
• Description: MC9S12DT256 Device User Guide V03.03
• Manufacturer: Motorola

MC9S12DT256 Device User Guide — V03.03
2.3.3 TEST — Test Pin
This input only pin is reserved for test.
NOTE:
The TEST pin must be tied to VSS in all applications.
2.3.4 VREGEN — Voltage Regulator Enable Pin
This input only pin enables or disables the on-chip voltage regulator.
2.3.5 XFC — PLL Loop Filter Pin
PLL loop filter. Please ask your Motorola representative for the interactive application note to compute
PLL loop filter elements. Any current leakage on this pin must be avoided.
XFC
R
0
C
P
MCU
C
S
VDDPLL
VDDPLL
Figure 2-3 PLL Loop Filter Connections
2.3.6 BKGD / TAGHI / MODC — Background Debug, Tag High, and Mode Pin
The BKGD/TAGHI/MODC pin is used as a pseudo-open-drain pin for the background debug
communication. In MCU expanded modes of operation when instruction tagging is on, an input low on
this pin during the falling edge of E-clock tags the high half of the instruction word being read into the
instruction queue. It is used as a MCU operating mode select pin during reset. The state of this pin is
latched to the MODC bit at the rising edge of RESET. This pin has a permanently enabled pull-up device.
2.3.7 PAD15 / AN15 / ETRIG1 — Port AD Input Pin of ATD1
PAD15 is a general purpose input pin and analog input AN7 of the analog to digital converter ATD1. It
can act as an external trigger input for the ATD1.
2.3.8 PAD[14:08] / AN[14:08] — Port AD Input Pins of ATD1
PAD14 - PAD08 are general purpose input pins and analog inputs AN[6:0] of the analog to digital
converter ATD1.
57