633
20.4.4
Input Sampling and A/D Conversion Time
The A/D converter has a built-in sample-and-hold circuit. The A/D converter samples the analog
input at a time t
D
after the ADST bit is set to 1, then starts conversion. Figure 20.6 shows the A/D
conversion timing. Table 20.4 indicates the A/D conversion time.
As indicated in figure 20.6, the A/D conversion time includes t
D
and the input sampling time. The
length of t
D
varies depending on the timing of the write access to ADCSR. The total conversion
time therefore varies within the ranges indicated in table 20.4.
In multi mode and scan mode, the values given in table 20.4 apply to the first conversion. In the
second and subsequent conversions the conversion time is fixed at 512 states when CKS = 0 or
256 states when CKS = 1.
Pø
Write
signal
ADF
*
1
Input sampling
timing
Legend
t
D
A/D conversion start delay
t
SPL
Input sampling time
t
CONV
A/D conversion time
Notes:
*
1 ADCSR write cycle
*
2 ADCSR address
Address
*
2
t
D
t
SPL
t
CONV
Figure 20.6 A/D Conversion Timing
Содержание SH7709S
Страница 2: ...Hitachi SuperH RISC engine SH7709S Hardware Manual ADE 602 250 Rev 1 0 09 21 01 Hitachi Ltd ...
Страница 75: ...56 ...
Страница 107: ...88 ...
Страница 125: ...106 ...
Страница 139: ...120 ...
Страница 203: ...184 ...
Страница 245: ...226 ...
Страница 292: ...273 T1 CKIO A25 to A0 CSn RD WR RD D31 to D0 WEn D31 to D0 BS T2 Read Write Figure 10 6 Basic Timing of Basic Interface ...
Страница 323: ...304 Tp TRr TRrw TRrw CKIO CKE CSn RAS3U RAS3L CASU CASL RD WR Figure 10 28 Synchronous DRAM Auto Refresh Timing ...
Страница 411: ...392 ...
Страница 609: ...590 ...
Страница 635: ...616 ...
Страница 663: ...644 ...
Страница 679: ...660 ...