UL
庐
LSI/CSI
LSI Computer Systems, Inc. 1235 Walt Whitman Road, Melville, NY 11747
LS7366R
(631) 271-0400 FAX (631) 271-0405
May 2006
PIN ASSIGNMENT
TOP VIEW
LSI
A3800
32-BIT QUADRATURE COUNTER WITH SERIAL INTERFACE
GENERAL FEATURES:
鈥?Operating voltage: 3V to 5.5V (V
DD
- V
SS
)
鈥?5V count frequency: 40MHz
鈥?3V count frequency: 20MHz
鈥?32-bit counter (CNTR).
鈥?32-bit data register (DTR) and comparator.
鈥?32-bit output register (OTR).
鈥?Two 8-bit mode registers (MDR0, MDR1)
for programmable functional modes.
鈥?8-bit instruction register (IR).
鈥?8-bit status register (STR).
鈥?Latched Interrupt output on Carry or Borrow or Compare or Index.
鈥?Index driven counter load, output register load or counter reset.
鈥?Internal quadrature clock decoder and filter.
鈥?x1, x2 or x4 mode of quadrature counting.
鈥?Non-quadrature up/down counting.
鈥?Modulo-N, Non-recycle, Range-limit or
Free-running modes of counting
鈥?8-bit, 16-bit, 24-bit and 32-bit programmable configuration
synchronous (SPI) serial interface
鈥?LS7366R (DIP), LS7366R-S (SOIC), LS7366R-TS (TSSOP)
- See Figure 1 -
SPI/MICROWIRE
(Serial Peripheral Interface):
鈥?Standard 4-wire connection: MOSI, MISO, SS/ and SCK.
鈥?Slave mode only.
GENERAL DESCRIPTION:
LS7366R is a 32-bit CMOS counter, with direct interface for quadra-
ture clocks from incremental encoders. It also interfaces with the
index signals from incremental encoders to perform variety of
marker functions.
For communications with microprocessors or microcontrollers, it
provides a 4-wire SPI/MICROWIRE bus.The four standard bus I/Os
are SS/, SCK, MISO and MOSI. The data transfer between a micro-
controller and a slave LS7366R is synchronous. The synchroniza-
tion is done by the SCK clocks supplied by the microcontroller. Each
transmission is organized in blocks of 1 to 5 bytes of data. A trans-
mission cycle is intitiated by a high to low transition of the SS/ input.
The first byte received in a transmission cycle is always an instruc-
tion byte, whereas the second through the fifth bytes are always
interpreted as data bytes. A transmission cycle is terminated with
the low to high transition of the SS/ input. Received bytes are shifted
in at the MOSI input, MSB first, with the leading edges (high transi-
tion) of the SCK clocks. Output data are shifted out on the MISO
output, MSB first, with the trailing edges (low transition) of the SCK
clocks.
7366R-050106-1
f
CKO
f
CKi
Vss
SS/
SCK
MISO
MOSI
1
2
3
4
5
6
7
14
V
DD
13
CNT_EN
12
A
11
B
10
INDEX/
9
DFLAG/
8
LFLAG/
FIGURE 1
LS7366R
Read and write commands cannot be combined.
For example, when the device is shifting out read
data on MISO output, it ignores the MOSI input,
even though the SS/ input is active. SS/ must be
terminated and reasserted before the device will
accept a new command.
The counter can be configured to operate as 1, 2, 3
or 4-byte counter. When configured as an n-byte
counter, the CNTR, DTR and OTR are all config-
ured as n-byte registers, where n = 1, 2, 3 or 4.
The content of the instruction/data identity is
automatically adjusted to match the n-byte configu-
ration. For example, if the counter is configured as a
2-byte counter, the instruction 鈥渨rite to DTR鈥?/div>
expects 2 data bytes following the instruction byte.
If the counter is configured as a 3-byte counter, the
same instruction will expect 3 bytes of data follow-
ing the instruction byte.
Following the transfer of the appropriate number of
bytes any further attempt of data transfer is ignored
until a new instruction cycle is started by switching
the SS/ input to high and then low.
The counter can be programmed to operate in a
number of different modes, with the operating
characteristics being written into the two mode
registers MDR0 and MDR1. Hardware I/Os are
provided for event driven operations, such as
processor interrupt and index related functions.
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9
10
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