NXP Semiconductors MPC5644A, Reference Manual, Page: 1071 / 1735

Enhanced Queued Analog-to-Digital Converter (EQADC)
MPC5644A Microcontroller Reference Manual, Rev. 6
Freescale Semiconductor 1071
25.6 Functional Description
25.6.1 Overview
The EQADC provides a parallel interface to two on-chip ADCs, a single master to single slave serial
interface to an off-chip external device and a parallel side interface to an on-chip companion module, like
a decimation filter. The two on-chip ADCs are architected to allow access to all the analog channels.
Initially, command data is contained in system memory in a user defined data structure which is likely to
be a queue as depicted in
Figure 25-1
1
. Command data is moved between the CQueues and CFIFOs by the
host CPU or by the DMAC which respond to interrupt and DMA requests generated by the EQADC. The
EQADC supports software and hardware triggers from other blocks or external pins to initiate transfers of
commands from the multiple CFIFOs to the on-chip ADCs or to the external device.
Table 25-47. ADC Pull Up/Down Control Register x (ADC_PUDCRx, x=0-7) field description
Field Description
2-3
CH_PULL x
[0:1]
Channel x Pull Up/Down Control bits
The CH_PULL x [0:1] field controls the pull up/down configuration of the channel x according
to Table 25-48 .
6-7
PULL_STR x
[0:1]
Pull Up/Down Strength Control bits of channel x
The PULL_STR x [0:1] bit field defines the strength of the channel x pull up or down resistors,
according to Table 25-49 .
Table 25-48. Channel x Pull Up/Down Field Definition
CH_PULLx[0:1] Definition
00 No Pull resistors connected to the channel
01 Pull Up resistor connected to the channel
10 Pull Down resistor connected to the channel
11 Pull Up and Pull Down resistors connected to the channel
Table 25-49. Pull Up/Down Strength Field Definition
PULL_STRx[0:1] Definition
00 Reserved
01 200 Kohms pull resistor
10 100 Kohms pull resistor
11 5 Kohms (Approx.) pull resistor
1
1
This set is not available for CH_PULL_ x = 11.
1. Command and result data can be stored in the system memory in any user defined data structure. However, in this
document it will be assumed that the data structure of choice is a queue, since it is the most likely data structure to be used
and because queues are the only type of data structure supported by the DMAC.