Motorola MPC533 Reference Manual page 470

Programming the QADC64E Registers
MSB 1
0
Field —
SRESET 00
Addr
Bits Name
0:1 —
2:7 CWPQ1
8:9 —
10:15 CWPQ2
13.3.9 Conversion Command Word Table
The conversion command word (CCW) table is a RAM, 64 words long on 16-bit address
boundaries where 10-bits of each entry are implemented. A CCW can be programmed by
the software to request a conversion of one analog input channel. The CCW table is written
by software and is not modified by the QADC64E. Each CCW requests the conversion of
an analog channel to a digital result. The CCW specifies the analog channel number, the
input sample time, and whether the queue is to pause after the current CCW. The ten
implemented bits of the CCW word are read/write data, where they may be written when
the software initializes the QADC64E. The remaining 6-bits are unimplemented so these
read as zeros, and write operations have no effect. Each location in the CCW table
13-26
PRELIMINARY—SUBJECT TO CHANGE WITHOUT NOTICE
2 3 4 5
CWPQ1
11_1111
Figure 13-12. Status Register 1 (QASR1)
Table 13-12. QASR1 Bit Descriptions
Reserved
Command Word Pointer for Q1 — CWPQ1 allows the software to know what CCW was
last completed for queue 1. This field is a software read-only field, and write operations
have no effect. CWPQ1 allows software to read the last executed CCW in queue 1,
regardless of which queue is active. The CWPQ1 field is a CCW word pointer with a valid
range of 0 to 63.
In contrast to CWP, CPWQ1 is updated when the conversion result is written. When the
QADC64E finishes a conversion in queue 1, both the result register is written and the
CWPQ1 are updated.
Finally, when queue 1 operation is terminated after a CCW is read that is defined as BQ2,
CWP points to BQ2 while CWPQ1 points to the last CCW queue 1.
During the stop mode, the CWPQ1 is reset to 63, since the control registers and the analog
logic are reset. When the freeze mode is entered, the CWPQ1 is unchanged; it points to
the last executed CCW in queue 1.
Reserved
Command Word Pointer for Q2 — CWPQ2 allows the software to know what CCW was
last completed for queue 2. This field is a software read-only field, and write operations
have no effect. CWPQ2 allows software to read the last executed CCW in queue 2,
regardless which queue is active. The CWPQ2 field is a CCW word pointer with a valid
range of 0 to 63.
In contrast to CWP, CPWQ2 is updated when the conversion result is written. When the
QADC64E finishes a conversion in queue 2, both the result register is written and the
CWPQ2 are updated.
During the stop mode, the CWPQ2 is reset to 63, since the control registers and the analog
logic are reset. When the freeze mode is entered, the CWP is unchanged; it points to the
last executed CCW in queue 2.
MPC533 Reference Manual
6 7 8 9
—
00
0x30 4812 (QASR1_A)
Description
10 11 12 13
CWPQ2
11_1111
MOTOROLA
14 LSB
15