mc68hc912bc32 Freescale Semiconductor, Inc, mc68hc912bc32 Datasheet - Page 277

• Manufacturer Part Number: mc68hc912bc32
• Description: M68hc12 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Chapter 17
Analog-to-Digital Converter (ATD)
17.1 Introduction
The ATD is an 8-channel, 10-bit, multiplexed-input, successive-approximation, analog-to-digital
converter, accurate to ± 2 least significant bit (LSB). It does not require external sample and hold circuits
because of the type of charge redistribution technique used. The ATD converter timing is synchronized
to the system P clock. The ATD module consists of a 16-word (32-byte) memory-mapped control register
block used for control, testing, and configuration.
17.2 Functional Description
A single conversion sequence consists of four or eight conversions, depending on the state of the select
8-channel mode (S8CM) bit when ATDCTL5 is written. There are eight basic conversion modes. In the
non-scan modes, the SCF bit is set after the sequence of four or eight conversions has been performed
and the ATD module halts. In the scan modes, the SCF bit is set after the first sequence of four or eight
conversions has been performed, and the ATD module continues to restart the sequence. In both modes,
the CCF bit associated with each register is set when that register is loaded with the appropriate
conversion result. That flag is cleared automatically when that result register is read. The conversions are
started by writing to the control registers.
M68HC12B Family Data Sheet, Rev. 9.1
Freescale Semiconductor
277