Mailbox
MPU
Subsystem
L4 Peripheral
Interconnect
WakeM3
MAIL_U0_IRQ
MAILBOXn
(4x32-bit messages each)
(x8)
PRU-ICSS
MAIL_U3_IRQ
MAIL_U1_IRQ
MAIL_U2_IRQ
PRU0
PRU1
Mailbox
17.1.2 Integration
This device contains a single instantiation of the Mailbox module at the system level. The mailbox function
is made of eight sub-module mailboxes each supporting a 1-way communication between two initiators.
The communication protocol from the sender to the receiver is implemented with mailbox registers using
interrupts. The sender sends information to the receiver by writing to the mailbox. Interrupt signaling is
used to notify the receiver a message has been queued or the sender for overflow situation.
The eight mailboxes are enough to handle communications between the MPU Subsystem, PRU-ICSS
PRUs, and WakeM3. Note that because the WakeM3 has access only to L4_Wakeup peripherals it does
not have access to the Mailbox registers. A mailbox interrupt can still be sent to the M3 to trigger message
notification. The actual message payload must be placed in either M3 internal memory or in the Control
Module Interprocessor Message registers (IPC_MSG_REG{0-7}).
Figure 17-1. Mailbox Integration
17.1.2.1 Mailbox Connectivity Attributes
The general connectivity for the Mailbox is shown in
Table 17-1. Mailbox Connectivity Attributes
Attributes
Type
Power Domain
Peripheral Domain
Clock Domain
L4PER_L4LS_GCLK
Reset Signals
PER_DOM_RST_N
Idle/Wakeup Signals
Smart Idle
Interrupt Requests
4 Interrupts
mail_u0 (MBINT0) – to MPU Subsystem
mail_u1 – to PRU-ICSS (PRU0)
mail_u2 – to PRU-ICSS (PRU1)
mail_u3 – to WakeM3
DMA Requests
None
Physical Address
L4 Peripheral slave port
17.1.2.2 Mailbox Clock and Reset Management
The mailbox function operates from the L4 interface clock.
3237
SPRUH73H – October 2011 – Revised April 2013
Interprocessor Communication
Copyright © 2011–2013, Texas Instruments Incorporated