Legacy-Free Keyboard/Embedded Controller with SPI and LPC Docking Interface
Chapter 17 Mailbox Register Interface
17.1
Overview
The Mailbox Registers Interface provides a standard run-time mechanism for the host to communicate
with the 8051 and other logical components in the LPC47N350. The Mailbox Registers Interface
includes a total of 52 index-addressable 8-bit registers (Table 17.1) and two 8-bit host access ports
(Table 17.3). Thirty-two of these 52 registers are 8051 Mailbox registers.
The Mailbox Registers Interface host access ports are run-time registers that occupy two addresses in
the system I/O space. The access ports are used by the host to read and write the 48 registers. The
access ports base address is determined by the Mailbox Registers Interface Base Address that is
initialized in Logical Device Number 9 in LPC47N350 configuration registers CR60 and CR61
(Table 17.2).
The 32 Mailbox registers as well as the PWM registers and Flash registers are directly addressable by
the 8051 through Memory-Mapped Control Registers (see Table 7.7, “8051 On-Chip External Memory
Mapped Registers,” on page 50).
In this specification, the registers in the Mailbox Registers Interface are identified by the prefix MBX in
front of a hexadecimal index address. Table 17.1 summarizes the 52 registers in the Mailbox Registers
Interface.
Table 17.1 Mailbox Registers Interface
MAILBOX
INDEX
8051
SYSTEM
R/W
ADDR.
(7F00+)
8051
R/W
POWER VCC1 VCC2
REGISTER NAME
ADDR
PLANE
POR
POR
NOTES
Flash Low Address
Flash Data
MBX80h
MBX81h
MBX82h
R/W
B1h
B2h
08h
R/W
VCC1
00h
-
-
-
System-to-8051
RC
Mailbox register 0-
8051-to-system
MBX83h
RC
09h
R/W
R/W
R/W
R/W
Note 17.1
Note 17.2
Mailbox register 1
Mailbox register [2-F]
MBX 84h-
91h
R/W
0Ah –
17h
PWM0 Speed Control
register
MBX92h
25h
PWM1 Speed Control
register
MBX93h
26h
8051STP_CLK
MBX94h
MBX95h
MBX96h
MBX97h
MBX98h
-
29h
-
-
R/W
-
PWM2 register
VCC2
ESMI source register
ESMI mask register
00h
00h
-
-
PWM3 Speed Control
Register
95h
R/W
VCC1
-
00h
04h
PWM3 Control Register
Reserved
MBX99h
MBX9Ah
96h
-
R/W
-
R
-
SMSC LPC47N350
191
Revision 1.1 (01-14-03)
DATASHEET
SMSC [ SMSC CORPORATION ]
