h8s-2138 Renesas Electronics Corporation., h8s-2138 Datasheet - Page 619

• Manufacturer Part Number: h8s-2138
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

19.4.3
The A/D converter has an on-chip sample-and-hold circuit. The A/D converter samples the analog
input at a time t
conversion timing. Table 19.4 indicates the A/D conversion time.
As indicated in figure 19.5, the A/D conversion time includes t
length of t
time therefore varies within the ranges indicated in table 19.4.
In scan mode, the values given in table 19.4 apply to the first conversion time. In the second and
subsequent conversions the conversion time is fixed at 256 states when CKS = 0 or 128 states
when CKS = 1.
State of channel 0 (AN0)
State of channel 1 (AN1)
State of channel 2 (AN2)
State of channel 3 (AN3)
Input Sampling and A/D Conversion Time
D
Notes: 1. Vertical arrows ( ) indicate instructions executed by software.
ADDRA
ADDRB
ADDRC
ADDRD
ADST
ADF
varies depending on the timing of the write access to ADCSR. The total conversion
D
2. Data currently being converted is ignored.
after the ADST bit is set to 1, then starts conversion. Figure 19.5 shows the A/D
Figure 19.4 Example of A/D Converter Operation
Idle
(Scan Mode, Channels AN0 to AN2 Selected)
Idle
A/D conversion 1
Idle
Set *
1
A/D conversion 2
Transfer
Continuous A/D conversion execution
Idle
A/D conversion result 1
A/D conversion 3
Idle
Rev. 4.00 Jun 06, 2006 page 565 of 1004
Idle
D
A/D conversion 4
A/D conversion time
and the input sampling time. The
A/D conversion result 2
A/D conversion result 3
Section 19 A/D Converter
A/D conversion 5
A/D conversion result 4
REJ09B0301-0400
Clear *
*
2
Idle
Idle
Idle
1
Clear *
1