QADC64E Legacy Mode Operation
MPC561/MPC563 Reference Manual, Rev. 1.2
13-50
Freescale Semiconductor
Figure 13-25. QADC64E Clock Programmability Examples
NOTE
PSA is maintained for software compatibility but has no functional benefit
to this version of the module.
The MCU IMB3 clock frequency is the basis of the QADC64E timing. The QADC64E requires that the
IMB3 clock frequency be at least twice the QCLK frequency. The QCLK frequency is established by the
combination of the PSH and PSL parameters in QACR0. The 5-bit PSH field selects the number of IMB3
clock cycles in the high phase of the QCLK wave. The 3-bit PSL field selects the number of IMB3 clock
cycles in the low phase of the QCLK wave.
Example 1 in
shows that when the PSH = 19, the QCLK remains high for 20 cycles if the
IMB3 clock and with PSL = 7 the QCLK remains low for 8 IMB3 clock cycles. Example 2 shows that
when PSH = 11, QCLK is high for 12 IMB3 clock cycles and with PSL = 7, QCLK is low for 8 IMB3
clock cycles. Finally, example 3 shows that with PSH = 7 and PSL = 7, QCLK alternates between high and
low every 8 IMB3 cycles.
Table 13-21. QADC64E Clock Programmability
Control Register 0 Information
Input Sample Time (IST) =0b00
Example
Number
Frequency
PSH
PSA
PSL
QCLK
(MHz)
Conversion Time
(
µ
s)
1
56 MHz
19
0
7
2.0
7.0
2
40 MHz
11
0
7
2.0
7.0
3
32 MHz
7
0
7
2.0
7.0
QCLK EXAMPLES
F
SYS
56 MHz EX1
40 MHz EX2
IMB3 CLOCK
QADC64E QCLK EX
32 MHz EX3
30 CYCLES
Summary of Contents for MPC561
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Page 144: ...Signal Descriptions MPC561 MPC563 Reference Manual Rev 1 2 2 46 Freescale Semiconductor...
Page 206: ...Central Processing Unit MPC561 MPC563 Reference Manual Rev 1 2 3 62 Freescale Semiconductor...
Page 302: ...Reset MPC561 MPC563 Reference Manual Rev 1 2 7 14 Freescale Semiconductor...
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Page 1144: ...Internal Memory Map MPC561 MPC563 Reference Manual Rev 1 2 B 34 Freescale Semiconductor...
Page 1212: ...TPU3 ROM Functions MPC561 MPC563 Reference Manual Rev 1 2 D 60 Freescale Semiconductor...
Page 1216: ...Memory Access Timing MPC561 MPC563 Reference Manual Rev 1 2 E 4 Freescale Semiconductor...