9
RM24C256C-L
DS-RM24C256C-L–081F–11/2016
addressed memory location. After the device receives the data, it performs an acknowledge. After the master has
received the last acknowledge (after the data byte) the master should send a STOP condition. The STOP condition
initiates the internal write cycle in the device. If the master does not send a STOP, the device will not write the data into
the addressed memory location.
While the device is in the write cycle it will not generate an acknowledge signal. Meanwhile, the master can poll the
device to determine when the write cycle is complete by sending it a control byte and looking for an acknowledge. Once
the write cycle has completed, the device will acknowledge a control byte sent to it.
If, in the RM24C256C-L, the byte written is the last byte in a 64-byte page, the address will wrap around to the beginning
of the same page. For instance, if the byte is written to address 007Fh, the incremented address will be 0000h. If the byte
is written to address 07FFh, the incremented address will be 0780h.
If a write cycle is attempted with the WP (write protect) pin held high, the device will acknowledge the command, address,
and data, but no write cycle will occur following the STOP command. The data will not be written, and the device will
immediately be available to accept a new command. However, the internal address pointer will be written; so after the
data byte is transmitted to the device and the STOP command issued by the master, the internal address pointer will
again be incremented by one.
Figure 6-1. Byte Write Cycle
7. Page Write Operation
Table 7-1. Density and Page Size
During a Page Write cycle, a page with up to 64 bytes of data can be written in one continuous write command. The Page
Write starts in the same manner as the Byte Write. In a Page Write, after the acknowledge following the first data byte,
the master does not send a STOP, but continues to send additional data bytes. (See Figure 7-1.) At the end of the
number of bytes to be written, the master sends a STOP command. Once the STOP command is sent, the device will
write all the data bytes into memory, starting at the address location given in the address bytes.
If the master should transmit more than 64 bytes prior to generating the STOP command, the internal 64-byte data buffer
in the device will wrap around and the first data bytes transmitted will be overwritten.
The internal address pointer will not increment beyond a page boundary but will instead wrap around to the first byte of
the addressed page.
As with the Byte Write cycle, once the STOP command is received the device enters a write cycle. During the write cycle,
the device will not generate an acknowledge signal. Meanwhile, the master can poll the device to determine when the
write cycle is complete by sending it a control byte and looking for an acknowledge. Once the write cycle has completed,
the device will acknowledge a control byte sent to it.
During the Page Write cycle, the first byte in the data byte buffer will be written in the address location indicated by the
address bytes transmitted to the device. Each successive data byte will be written in the successive address locations.
Product Density Page Size (byte)
RM24C256D 256 Kbit 64