BR93G46-3A Datasheet, PDF (15/39 Pages) Rohm – Serial EEPROM series Standard EEPROM

BR93G46-3A
Datasheet
●Description of operations
Communications of the MicroWire BUS are carried out by SK (serial clock), DI (serial data input),DO (serial data output) ,and
CS (chip select) for device selection.
When to connect one EEPROM to a microcontroller, connect it as shown in Figure 34(a) or Figure 34(b). When to use the
input and output common I/O port of the microcontroller, connect DI and DO via a resistor as shown in Figure 34(b) (Refer to
pages 21, 22.), and connection by 3 lines is available.
In the case of plural connections, refer to Figure 34 (c).
Micro-
controller
Micro-
BR93GXX
Micro-
BR93GXX
CS3
controller
controller
CS2
CS
CS
CS
CS
CS1
SK
SK
SK
SK
SK
DO
DI
DO
DI
DI/O
DI
DI
DO
DO
Device 1
Device 2
Device 3
(a). Connection by 4 lines
(b). Connection by 3 lines
(c). Connection example of plural devices
Figure 34. Connection method with microcontroller
Communications of the MicroWire BUS are started by the first “1” input after the rise of CS. This input is called a start bit.
After input of the start bit, input ope code, address and data. Address and data are input all in MSB first manners.
“0” input after the rise of CS to the start bit input is all ignored. Therefore, when there is limitation in the bit width of PIO of the
microcontroller, input “0” before the start bit input, to control the bit width.
●Command mode
Command
Start
bit
Read (READ) *1
1
Write enable (WEN) 1
Write disable (WDS) 1
Write (WRITE) *2
1
Write all (WRAL) *2 1
Erase (ERASE)
1
Erase all (ERAL)
1
Ope
code
10
00
00
01
00
11
00
Address
BR93G46-3
MSB of Address(Am) is A5
A5,A4,A3,A2,A1,A0
1 1 ****
0 0 ****
A5,A4,A3,A2,A1,A0
0 1 ****
A5,A4,A3,A2,A1,A0
1 0 ****
Data
MSB of Data(Dx) is D15
Required clocks(n)
D15~D0(READ DATA) BR93G46-3:n=25
BR93G46-3:n=9
D15~D0(WRITE DATA)
D15~D0(WRITE DATA)
BR93G46-3:n=25
BR93G46-3:n=9
・ Input the address and the data in MSB first manners.
・ As for *, input either “1” or “0” .
*Start bit
Acceptance of all the commands of this IC starts at recognition of the start bit.
The start bit means the first “1” input after the rise of CS.
*1 As for read, by continuous SK clock input after setting the read command, data output of the set address starts, and address data in significant order are
sequentially output continuously. (Auto increment function)
*2 For write or write all commands, an internal erase or erase all is included and no separate erase or erase all is needed before write or write all command.
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