M48T212V-85MH1 Просмотр технического описания (PDF) - STMicroelectronics
Номер в каталоге
Компоненты Описание
производитель
M48T212V-85MH1 Datasheet PDF : 32 Pages
| |||
M48T212Y, M48T212V
READ Mode
The M48T212Y/V executes a READ cycle when-
ever W (WRITE Enable) is high and E (Chip En-
able) is low. The unique address specified by the
address inputs (A3-A0) defines which one of the
on-chip TIMEKEEPER® registers is to be access-
ed. When the address presented to the
M48T212Y/V is in the range of 0h-Fh, one of the
on-board TIMEKEEPER registers is accessed and
valid data will be available to the eight data output
drivers within tAVQV after the address input signal
is stable, providing that the E and G access times
are also satisfied.If they are not, then data access
must be measured from the latter occurring signal
(E or G) and the limiting parameter is either tELQV
for E or tGLQV for G rather than the address access
time.
When EX input is low, an external SRAM location
will be selected.
Note: Care should be taken to avoid taking both E
and EX low simultaneously to avoid bus conten-
tion.
Figure 6. READ Cycle Timing: RTC Control Signal Waveforms
READ
READ
tAVAV
tAVAV
ADDRESS
WRITE
tAVAV
tELQV
tAVQV
tAVWL
E
tELQX
G
tGLQV
tWLWH
tWHAX
W
DQ7-DQ0
tGLQX
tAXQX
DATA OUT
VALID
DATA OUT
VALID
tGHQZ
DATA IN
VALID
Note: EX is assumed High.
AI02640
Table 5. READ Mode AC Characteristics
M48T212Y
M48T212V
Symbol
Parameter(1)
–70
–85
Unit
Min
Max
Min
Max
tAVAV Read Cycle Time
70
85
ns
tAVQV Address Valid to Output Valid
70
85
ns
tELQV Chip Enable Low to Output Valid
70
85
ns
tGLQV Output Enable Low to Output Valid
25
35
ns
tELQX(2) Chip Enable Low to Output Transition
5
5
ns
tGLQX(2) Output Enable Low to Output Transition
0
0
ns
tEHQZ(2) Chip Enable High to Output Hi-Z
20
25
ns
tGHQZ(2) Output Enable High to Output Hi-Z
20
25
ns
tAXQX Address Transition to Output Transition
5
5
ns
Note: 1. Valid for Ambient Operating Temperature: TA = 0 to 70°C or –40 to 85°C; VCC = 4.5 to 5.5V or 3.0 to 3.6V (except where noted).
2. CL = 5pF.
10/32
Share Link: 