TSS463-AAR ATMEL [ATMEL Corporation], TSS463-AAR Datasheet - Page 8

• Manufacturer Part Number: TSS463-AAR
• Description: VAN Data Link Controller with Serial Interface
• Manufacturer: ATMEL [ATMEL Corporation]

Intel SPI Mode
Figure 5. Typical Application With the 8051 UART in Mode 0
8
TSS463-AA
Remaining pins
RESET (1)
PORT X.z
PORT X.y
XTAL1
TXD
RXD
IRQ
When the master (CPU) conducts a read, it sends an address byte, a control byte and
dummy characters ("0xFF" for instance) on its MOSI line. In the case of a VAN mes-
sages RAM read (VAN frame received), the first data byte sent back by the TSS463AA
on its MISO pin is the data length so the master knows how many dummy characters it
must send to read the VAN frame properly. When the TSS463AA responds back with
data, it will not take care of the MOSI line.
The master must activate and de-activate SS between each data frame.
Synchronization bytes must be monitored carefully. For instance, if “0xAA” and “0x55”
are not monitored correctly, then the previous transmission may be incorrect too.
A control byte containing "0x00" or "0xFF" is forbidden except during an "Initialization
Sequence".
The Intel SPI mode is the second type of interface. As mentioned before, the TSS463AA
enters this mode if the Initialization Sequence contains (first two bytes received) "0xFF,
0xFF".
This mode is fully compatible to the Intel UART serial interface programmed in mode 0
only. It is the same as Motorola SPI mode (same CPOL and CPHA) but with inverted
communication sense (LSB first and MSB last). The protocol is also the same.
However, from the master point of view (host microcontroller), the hardware is different.
Figure 5 shows how to connect the TSS463AA and Intel type microcontroller.
Notes:
General I/O
1. The RESET pin can either be connected to GND through a 1 µF capacitor, or the
microcontroller RESET pin or unconnected (inactive with internal pull-up).
C1
C2
optional
(if needed)
100k
TEST/VSS
INT
VDD
XTAL1
CKOUT
XTAL2
MISO
SS
1
2
3
4
5
6
7
8
15
16
14
13
12
11
10
9
MOSI
SCLK
RxD1
RESET (1)
GND
TXD
RxD0
RxD2
VAN Bus
4205B–AUTO–12/04