82C237
Timing Waveforms (Continued)
SI
SI
S0
S0
S1
S2
S3
S4
S2
S3
S4
SI
SI
SI
CLK
TCY
(14)
TCL (13)
TQS
(30)
TQS
(30)
TCH
(12)
DREQ
TDQ
(18)
TDQ
(18)
HRQ
DWLE
(SEE NOTE)
TASS
(11)
TAHS
(7)
THS
(25)
HLDA
AEN
TAET
(2)
TAEL
(1)
TEPS
(20)
TCLSL
(34)
TRHAL
(58)
TEPH
(19)
TCLSH
(33)
TSHSL
(37)
ADSTB
TASS
(11)
TAK (9)
TFADB
(24)
TAHS
(7)
DB0-DB7
TASM
(10)
TAHW
(8)
A8-A15
TAFDB
(5)
TAFAB (3)
TAHW (8)
TFAAB
(22)
A0-A7
ADDRESS VALID
ADDRESS VALID
TAHR (6)
TAHR
(6)
(64)
TAZRL
TAK
(9)
TRHDI (63)
TDCTR
TAVRL
(56)
TDCL
(15)
TRLRH
(36)
DACK
READ
TDCL
(15)
(16)
TAFC (4)
TDCTR (16)
TFAC
(23)
TWRRD
(35)
TDCTW
(17)
TAVWL
(57)
TDVAL (61)
TDCL (15)
TDCTW (17)
TWLWH (39)
WRITE
(FOR EXTENDED WRITE)
TAK (9)
TAK (9)
TDVWL TWLWHA
(62) (38)
TDCL
(15)
INT EOP
(FOR EXTENDED WRITE)
TEPW (21)
EXT EOP
FIGURE 12. DMA TRANSFER
NOTE: For 16-bit mode, 82C237 only. In 8-bit mode this signal is always high impedance three-stated. Waveform shown is for an 8-bit transfer
with the 82C237 programmed in 16-bit mode. For a 16-bit transfer, DWLE will go low at least TASS before the falling edge of ADSTB in S2,
and remain low for the entire transfer.
4-169
INTERSIL [ Intersil ]
