48LM01-ISLASHSM datasheet(20/40 Pages) MICROCHIP

20 / 40 page

 2018-2019 Microchip Technology Inc.

DS20006008C-page 20

48L512/48LM01

9.0

NONVOLATILE USER SPACE

ACCESS

Both the 512K and 1M devices have 16 bytes (128

bits) of nonvolatile user space memory.

The nonvolatile user space memory is accessed

through the WRNUR and RDNUR instructions. Data

written to the nonvolatile user space memory is volatile

but will be transferred to EEPROM automatically on

any power disruption. The last content will then be

restored from EEPROM on the next power up.

Software Store and Software Recall can also be

executed by the user as described in Section 11.0

"Store/Recall Operations".

9.1

Write Nonvolatile User Space

(WRNUR)

Writing to the 16-byte nonvolatile user space requires

the WEL bit to be set, such as with a WREL instruction.

The nonvolatile user space write operation must

include the CS pin to be brought low, the WRNUR

instruction to be sent on SI, and the whole NU value

clocked in (16-bytes). Then the CS pin is set high. The

value is stored immediately in the volatile memory.

The nonvolatile user space value is not transferred to

EEPROM until the next power disruption, though a

Software Store can be executed at any time. The

nonvolatile user space content is then permanent only

until rewritten by the user.

FIGURE 9-1:

NONVOLATILE USER SPACE WRITE

9.2

Read Nonvolatile User Space

(RDNUR)

Reading the nonvolatile user space is possible with

the RDNUR command. The nonvolatile user space

read operation must include the CS pin to be brought

low, the RDNUR instruction to be sent on SI, and the

whole NU value clocked out on SO (16 bytes). Then

the CS pin is set high. The value read is from the

volatile SRAM memory, so this will be the last value

restored from EEPROM on power-up or any new value

written into these 16 bytes since the last power-up.

The user can also use the Software Recall command

(Section 11.0 "Store/Recall Operations") to recover

the nonvolatile user space content moved to EEPROM

on the last power event or the last Software Store

event.

FIGURE 9-2:

READ NONVOLATILE USER SPACE

9 1011 1213 1415

WRNUR

Instruction

NU byte 0

NU byte 15

SCK

567

765

43210

0000

76543

210

SCK

23456789 10 11

76543210

RDNUR

Instruction

NU Byte 0

High Impedance

543210

NU Byte 15

0011

12 13 14 15

48LM01-I/SM Scheda tecnica(PDF) 20 Page - Microchip Technology

48LM01-I/SM Scheda tecnica(HTML) 20 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

Scheda tecnica Scarica

Link URL