S39421 View Datasheet(PDF) - Summit Microelectronics
Part Name
Description
MFG CO.
'S39421' PDF : 28 Pages View PDF
S39421
INSTRUCTION SET
Instruction
Start
Bit
READ
1
ERASE
1
WRITE
1
EWEN
1
EWDS
1
WRAL
1
Opcode
10
11
01
00
00
00
Address
x16
x(A5–A0)
x(A5–A0)
x(A5–A0)
11xxxx
00xxxx
01xxxx
Data
x16
D15–D0
D15–D0
Comments
Read Address AN–A0
Clear Address AN–A0
Write Address AN–A0
Write Enable
Write Disable
Write All Addresses
2024 PGM T5 .0
Data Download Mode
The Data Download mode is an alternative method of
accessing the E2PROM memory. Use of this mode allows
downloading the entire contents of the memory without
entering any commands. The DD mode is enabled after a
low to high transition on the DD pin, while continuing to
assert DD (this includes powering up the device with DD
tied high). Also, as a condition to enter this mode, the
device must not be in a state of reset. Once in Data
Download mode, the device will wait until Chip Select is
driven active. At this point, the device will output a dummy
‘0’ followed by the contents of location 0000. As long as
the SK line is toggled the S39421 will continue to output
the contents of sequential address locations. In this
manner, the configuration data that is loaded into an
interface device can be accessed in a simple manner
without requiring the logic of the interface chip to generate
the complex signals needed for the microwire interface.
Data Download mode is exited upon the first high to low
transition of the Chip Select input.
VCC
RESET
DD
CS
SK
DO
DD Mode Enabled After
RESET is released and After
DD is Taken to Logic 1
DD Mode
Disabled
Dummy 0
Data From
Address 000
Data From
Address 001 Data From
Address 1FE
Data From
Address 1FF
FIGURE 11. DATA DOWNLOADER SEQUENCE OF OPERATION
[note: all data download timing conforms to the timing shown in Figure 5]
2024 ILL7.1
2024 9.0 8/8/00
13
Share Link: 
