Intel 8253 - Page 678

4-18
FIGURE 13. READ/INTA
FIGURE 14. OTHER TIMING
NOTES:
1. Interrupt Request (IR) must remain HIGH until leading edge of first
INTA.
2. During first INTA the Data Bus is not active in 80C86/88/286 mode.
3. 80C86/88/286 mode.
4. 8080/8085 mode.
FIGURE 15. INTA SEQUENCE
Timing Waveforms (Continued)
RD/INTA
EN
CS
ADDRESS BUS
DATA BUS
(20)
TAHDV
(14)
TRLDV
(1)
TAHRL
(18)
TRLEL
(3)
TRLRH
(19)
TRHEH
(2)
TRHAX
(15)
TRHDZ
A
0
(11)
TRHRL
(12)
TWHWL
(13)
TCHCL
RD
INTA
WR
RD
INTA
WR
RD
INTA
WR
IR
(9)
TJLJH
INT
INTA
SEE NOTE 1
DB
CAS 0 - 2
TCVIAL
(10)
SEE
NOTE 2
(17)
TIALCV
(21)
TCVDV
(10)
TCVIAL
SEE NOTE 3 SEE NOTE 4
(16)
TJHIH
82C59A