z16f2811 ZiLOG Semiconductor, z16f2811 Datasheet - Page 155

• Manufacturer Part Number: z16f2811
• Description: High Performance Microcontrollers
• Manufacturer: ZiLOG Semiconductor

PS022006-0207
1
0
Idle State
of Line
Figure 27. LIN-UART Asynchronous MULTIPROCESSOR Mode Data Format
The character format is given below:
In MULTIPROCESSOR (9-bit) mode, the
MULTIPROCESSOR control bit. The LIN-UART Control 1 and Status 1 registers provide
MULTIPROCESSOR (9-bit) mode control and status information. If an automatic address
matching scheme is enabled, the LIN-UART address compare register holds the network
address of the device.
MULTIPROCESSOR (9-bit) Mode Receive Interrupts
When MULTIPROCESSOR mode is enabled, the LIN-UART processes only frames
addressed to it. You can determine whether a frame of data is addressed to the LIN-UART is
made in hardware, software or a combination of the two, depending on the multiprocessor
configuration bits. In general, the address compare feature reduces the load on the CPU
because it does not need to access the LIN-UART when it receives data directed to other
devices on the multi-node network. The following 3 MULTIPROCESSOR modes are
available in the hardware:
1. Interrupt on all address bytes.
2. Interrupt on matched address bytes and correctly framed data bytes.
3. Interrupt only on correctly framed data bytes.
These modes are selected with MPMD[1:0] in the LIN-UART Control 1 register. For all
MULTIPROCESSOR modes, bit MPEN of the LIN-UART Control 1 register must be set to 1.
The first scheme is enabled by writing
address bytes cause an interrupt, while data bytes never cause an interrupt. The ISR checks
the address byte which triggered the interrupt. If it matches the LIN-UART address, the
software clears MPMD[0]. At this point, each new incoming byte interrupts the CPU. The
software determines the end of the frame and checks for it by reading the MPRX bit of the
LIN-UART Status 1 register for each incoming byte. If MPRX
the address of this new frame is different from the LIN-UART’s address, then MPMD[0]
must be set to 1 by software, causing the LIN-UART interrupts to go inactive until the next
Start
Bit0
lsb
Bit1
Bit2
P R E L I M I N A R Y
Bit3
Data Field
Bit4
01b
Parity
to MPMD[1:0]. In this mode, all incoming
Bit5
bit location (9th bit) becomes the
Bit6
msb
Bit7
=1
, a new frame has begun. If
Product Specification
ZNEO
MP
™
1
Stop Bit(s)
Z16F Series
2
LIN-UART
141