Datasheet

Table 19-13. Total conversion time vs. control conditions
Conversion type ADICLK ADLSMP Max total conversion time
Single or first continuous 8-bit 0x, 10 0 20 ADCK cycles + 5 bus clock cycles
Single or first continuous 10-bit or 12-bit 0x, 10 0 23 ADCK cycles + 5 bus clock cycles
Single or first continuous 8-bit 0x, 10 1 40 ADCK cycles + 5 bus clock cycles
Single or first continuous 10-bit or 12-bit 0x, 10 1 43 ADCK cycles + 5 bus clock cycles
Single or first continuous 8-bit 11 0 5 µs + 20 ADCK + 5 bus clock cycles
Single or first continuous 10-bit or 12-bit 11 0 5 µs + 23 ADCK + 5 bus clock cycles
Single or first continuous 8-bit 11 1 5 µs + 40 ADCK + 5 bus clock cycles
Single or first continuous 10-bit or 12-bit 11 1 5 µs + 43 ADCK + 5 bus clock cycles
Subsequent continuous 8-bit;
f
BUS
> f
ADCK
xx 0 17 ADCK cycles
Subsequent continuous 10-bit or 12-bit;
f
BUS
> f
ADCK
xx 0 20 ADCK cycles
Subsequent continuous 8-bit;
f
BUS
> f
ADCK
/11
xx 1 37 ADCK cycles
Subsequent continuous 10-bit or 12-bit;
f
BUS
> f
ADCK
/11
xx 1 40 ADCK cycles
The maximum total conversion time is determined by the selected clock source and the
divide ratio. The clock source is selectable by the ADC_SC3[ADICLK] bits, and the
divide ratio is specified by the ADC_SC3[ADIV] bits. For example, in 10-bit mode, with
the bus clock selected as the input clock source, the input clock divide-by-1 ratio
selected, and a bus frequency of 8 MHz, then the conversion time for a single conversion
as given below:
The number of bus cycles at 8 MHz is:
Note
The ADCK frequency must be between f
ADCK
minimum and
f
ADCK
maximum to meet ADC specifications.
Chapter 19 Analog-to-digital converter (ADC)
MC9S08PA60 Reference Manual, Rev. 1, 9/2012
Freescale Semiconductor, Inc. 541