Datasheet

Table Of Contents
I/O Registers
MC68HC908GR60A • MC68HC908GR48A • MC68HC908GR32A Data Sheet, Rev. 5
Freescale Semiconductor 67
3.8.2 ADC Data Register High and Data Register Low
3.8.2.1 Left Justified Mode
In left justified mode, the ADRH register holds the eight MSBs of the
10-bit result. The ADRL register holds the two LSBs of the 10-bit result. All other bits read as 0. ADRH
and ADRL are updated each time an ADC single channel conversion completes. Reading ADRH latches
the contents of ADRL until ADRL is read. All subsequent results will be lost until the ADRH and ADRL
reads are completed.
1 0 0 0 0 PTG0/AD16
1 0 0 0 1 PTG1/AD17
1 0 0 1 0 PTG2/AD18
1 0 0 1 1 PTG3/AD19
1 0 1 0 0 PTG4/AD20
1 0 1 0 1 PTG5/AD21
1 0 1 1 0 PTG6/AD22
1 0 1 1 1 PTG7/AD23
1
1
1
1
0
1
0
0
0
0
Unused
11101
V
REFH
11110
V
REFL
1 1 1 1 1 ADC power off
1. If any unused channels are selected, the resulting ADC conversion will be unknown or re-
served.
Address: $003D ADRH
Bit 7654321Bit 0
Read: AD9 AD8 AD7 AD6 AD5 AD4 AD3 AD2
Write:
Reset: Unaffected by reset
Address: $003E ADRL
Read:AD1AD0000000
Write:
Reset: Unaffected by reset
= Unimplemented
Figure 3-5. ADC Data Register High (ADRH) and Low (ADRL)
Table 3-1. Mux Channel Select
(1)
(Continued)
ADCH4 ADCH3 ADCH2 ADCH1 ADCH0 Input Select