Motorola ColdFire MCF5281 - Manual (Page 548)

Queued Analog-to-Digital Converter (QADC)
28-10 Freescale Semiconductor
28.6.5 Control Registers
This subsection describes the QADC control registers.
28.6.5.1 QADC Control Register 0 (QACR0)
QACR0 establishes the QADC sampling clock (QCLK) with prescaler parameter fields and defines
whether external multiplexing is enabled. Typically, these bits are written once when the QADC is
initialized and not changed thereafter. The bits in this register are read anytime, write anytime (except
during stop mode).
7 6 5 4 3 2 1 0
Field — DDQB3 DDQB2 DDQB1 DDQB0
Reset 0000_0000
R/W R
Address IPSBAR + 0x19_0009
Figure 28-7. Port QB Data Direction Register (DDRQB)
15 14 13 12 11 8
Field MUX — TRG —
Reset 0000_0000
R/W: R/W R R/W R
7 6 5 4 3 2 1 0
Field — QPR6 QPR5 QPR4 QPR3 QPR2 QPR1 QPR0
Reset 0001_0011
R/W: R R/W
Address IPSBAR + 0x19_000a, 0x19_000b
Figure 28-8. QADC Control Register 0 (QACR0)
Table 28-4. QACR0 Field Descriptions
Bit(s) Name Description
15 MUX Externally multiplexed mode. Configures the QADC for operation in externally
multiplexed mode, which affects the interpretation of the channel numbers and forces
the MA[1:0] signals to be outputs.
1 Externally multiplexed, up to 18 possible channels
0 Internally multiplexed, up to 8 possible channels
14–13 — Reserved, should be cleared.
12 TRG Trigger assignment. Determines the queue assignment of the ETRIG[2:1] signals.
1 ETRIG1 triggers queue 2; ETRIG2 triggers queue 1.
0 ETRIG1 triggers queue 1; ETRIG2 triggers queue 2.
MCF5282 and MCF5216 ColdFire Microcontroller User’s Manual, Rev. 3