1). Referring to AT24C01A, I'm confused (as I'm newbie in microcontroller), is it 128 bytes or 1 K bytes ?. If 128 bytes, then last address is 7FH, and if 1024 bytes, then last address is 3FF ?.

2). Below is the quote you posted in other thread for DS1307.

You wrote :
i am writing some steps how to read from DS1307
Start
Send slave address with write bit
send the subaddress from where you want to read
start condition again [NOTE:dont send stop before this]
send slave address with read bit
start reading.
So the above steps are applied in the code as..

run1: acall startc
mov a,#0d0h
acall send
mov a,#00h
acall send
mov r6,#3fh
acall startc
mov a,#0d1h
acall send
mov r0,#40h
here: acall recv
djnz r6,here
acall stop

If I understand it correctly, 3FH = last address in DS1307 and we inserted 40H into R0 simply to tell the microcontroller it is the last data to be read ?.

In DS1307, normally only two data were stored inside, that is hour and minute (alarm) time. Even only two data were stored into the DS1307, the microcontroller will read the entire memory from 00H to 3FH and end the process if reach 40H ?.

Can this procedures (read the entire address) applied to AT24C01A ?. What about when writing to AT24C01A ?.

3). If I have 10 data to be stored into the AT24C01A, for example : Data_1,............, Data_10, do I need to make a descriptions like this : Data_1 equ 00H, Data_2 equ 1H,..........Data_10 equ 9H (to specify each data address in AT24C01A RAM) ?.

Sorry for the long post.

Thanks,
SGH