Datasheet

MCP414X/416X/424X/426X
DS22059B-page 48 © 2008 Microchip Technology Inc.
7.4 Continuous Commands
The device supports the ability to execute commands
continuously. While the CS
pin is in the active state (V
IL
or V
IHH
). Any sequence of valid commands may be
received.
The following example is a valid sequence of events:
1. CS pin driven active (V
IL
or V
IHH
).
2. Read Command.
3. Increment Command (Wiper 0).
4. Increment Command (Wiper 0).
5. Decrement Command (Wiper 1).
6. Write Command (Volatile memory).
7. Write Command (Non-Volatile memory).
8. CS
pin driven inactive (V
IH
).
TABLE 7-3: COMMANDS
Note 1: It is recommended that while the CS pin is
active, only one type of command should
be issued. When changing commands, it
is recommended to take the CS
pin
inactive then force it back to the active
state.
2: It is also recommended that long
command strings should be broken down
into shorter command strings. This
reduces the probability of noise on the
SCK pin corrupting the desired SPI
command string.
Command Name
# of
Bits
Writes
Value in
EEPROM
Operates on
Volatile/
Non-Volatile
memory
High
Voltage
(V
IHH
) on
CS
pin?
Impact on
WiperLock or
Write Protect
Works
when
Wiper is
“locked”?
Write Data 16-Bits Yes
(1)
Both — unlocked
(1)
No
Read Data 16-Bits — Both — unlocked
(1)
No
Increment Wiper 8-Bits — Volatile Only — unlocked
(1)
No
Decrement Wiper 8-Bits — Volatile Only — unlocked
(1)
No
High Voltage Write Data 16-Bits Yes Both Yes unchanged No
High Voltage Read Data 16-Bits — Both Yes unchanged Yes
High Voltage Increment Wiper 8-Bits — Volatile Only Yes unchanged No
High Voltage Decrement Wiper 8-Bits — Volatile Only Yes unchanged No
Modify Write Protect or Wiper-
Lock Technology (High Voltage) -
Enable
8-Bits —
(2)
Non-Volatile
Only
(2)
Yes locked/
protected
(2)
Yes
Modify Write Protect or Wiper-
Lock Technology (High Voltage) -
Disable
8-Bits —
(3)
Non-Volatile
Only
(3)
Yes unlocked/
unprotected
(3)
Yes
Note 1: This command will only complete if wiper is “unlocked” (WiperLock Technology is Disabled).
2: If the command is executed using address 02h or 03h, then that corresponding wiper is locked or
if with address 0Fh, then Write Protect is enabled.
3: If the command is executed using with address 02h or 03h, then that corresponding wiper is unlocked or
if with address 0Fh, then Write Protect is disabled.