Actel MC-ACT-UARTF-NET Fast uart Datasheet

MC-ACT-UARTF
Fast UART
February 25, 2003
Datasheet v1.3
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URL: www.memecdesign.com/actel
TM
Product Summary
Intended Use
•
Industry Standard Serial Interfaces
•
System Peripherals
•
Debug/Maintenance Interfaces
Key Features
•
Baudrate Synthesizer for any baudrate up to 1/10 of clock speed
•
No dedicated clock frequency
•
7 or 8 Bits Data
•
No/Odd/Even Parity
•
•
Error Detection
1 or 2 Stop Bits
•
Format Check
•
3-Point Input Sampling
•
Parallel Interface with Event Control
Targeted Devices
•
SX-A Family
•
Axcelerator Family
•
ProASIC
PLUS
Family
General Description
The MC-ACT-UARTF core is generally used as a data link layer with parallel interfaces and event communication.
Microprocessor specific interfaces are built around the MC-ACT-UARTF, as well queues, interrupt controllers and
1
status reporting circuits .
1
For complete UART solutions, please contact Memec Design.
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Memec Design
Core Deliverables
•
Netlist Version
o Netlist compatible with the Actel Designer place and route tool
•
RTL Version
o VHDL Source Code
o Test Bench
•
All
o
User Guide
Synthesis and Simulation Support
•
Synthesis: Synplicity
•
Simulation: ModelSim
•
Other tools supported upon request
Verification
•
Test Bench
clk
reset_n
UART-F
fuart_tx_data
fuart_tx_we
fuart_tx_busy
TX Unit
fuart_tx_pin
fuart_rx_pin
fuart_rx_data
RX Unit
fuart_rx_ready
fuart_par_error
fuart_form_error
fuart_config.data_78
fuart_config.par_ebl
fuart_config.par_pol
fuart_config.stop_12
fuart_config.tx_run
fuart_config.rx_run
fuart_config.baudrate
Configuration
Figure 1:Block Diagram
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Functional Description
Structure of UART-F
The structure of MC-ACT-UARTF consists of four principal block. A dual advanced high speed baudrate synthesizer
is implemented to serve as receiver sampling source and transmitter clock source. Clock generation is configured
through 16-bit register value.
Format analyzer detects the incoming data stream to sequence bits stored and interface by receive unit. The
detection and derivation of data stream enables a bit sampling mechanism to reduce necessary clock cycle in
receiving unit.
Transmit unit is starting serial out after a parallel event controlled interface is used.
Config
Dual Advanced Hi Speed
Baudrate Synthesizer
RX Data
RX Ctrl
Receive
Unit
Format
Analyzer
serial in
TX Data
TX Ctrl
Transmit
Unit
serial out
UART-F
Figure 2: UART-F Structure
Event Communication
For communicating events, the MC-ACT-UARTF core uses or produces active ‘1’ pulses, which are activated for
only one clk cycle. In the inactive state, they remain low with respect to the rising clk edge, so glitches may occur.
For communicating over clock domains, these events must be synchronized first!
Configuration
The configuration pins are used to set the bitrate, bit timing and output format. They’re static inputs and used for
both receiver and transmitter in common.
Baudrate
The baudrate generator is not a simple prescaler, but allows generating all baudrates from the system clock within a
certain range. There is no special clock frequency needed for that purpose so that you’re free to choose the system
clock for the MC-ACT-UARTF, which simplifies considerably the clock structure.
To configurate the baudrate a 16bit configuration register value is used.
Examples:
For 1Mhz clock and 115’200bps, n is 30198(dec), accuracy better than 33ppm,
For 20Mhz clock and 1Mbps, n is 13107(dec), accuracy better than 76ppm.
Limitations:
Values for n lower than 100(dec) should not be used, otherwise the accuracy may be below 1%.
e.g. for 1MHz clock, the possible baudrates with accuracy better than 1% range from 381bps to 250kbps.
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Accuracy:
The worst case accuracy can be calculated by simply inversing the value n. Therefore, a value larger than 100 will
guarantee accuracy better than 1%, values larger than 1000 produce results better than 0.1%.
Jitter:
The faster the baudrate, the better the accuracy, but more relative jitter is added. Maximum absolute jitter is always
equal 1/fclk.
Serial Interface
The serial interface includes the receive and transmit path separately. It is full a duplex solution, receive and
transmit is possible at the same time.
Transmitter Interface
For transmitting data, a parallel event controlled interface is used. It is an efficient way to embed the MC-ACTUARTF in systems as well as connecting simple or complex specific interfaces, including queues etc., to it.
The transmitter path stores the incoming byte in the shift register by means of the fuart_tx_we signal and starts the
transmitting activity. fuart_tx_busy goes high also and remains high until the data is sent.
Receiver Interface
For receiving data, a similar type of interface is used as in the transmitter path
The receiver path contains several checks and special features. First, the level at the fuart_rx_pin is watched. When
a falling edge is detected, the receiver is started. A reception is started only when the start bit after a falling edge is
detected low. If parity is enabled, it is checked and event failures are reported on fuart_par_error. Missing stop bits
(level not zero) are reported as format checks. In all error cases, the data byte is aborted and the error reason is
reported. Please note that fuart_rx_ready is not asserted when error reporting is done.
Device Requirements
Family
SX-A
PLUS
ProASIC
Axcelerator
Device
COMB
274 (54%)
n/a
270 (5%)
SX08A-3
APA075-STD
AX500-3
Utilization
SEQ
104 (41%)
n/a
104 (4%)
Performance
Total
378 (50%)
659 (22%)
374 (5%)
142 MHz
70 MHz
153 MHz
Table 1: Device Utilization and Performance
Verification and Compliance
Complete functional and timing simulation has been performed on the UART-F using ModelSim 5.5d. The UART-F
core has been used successfully in customer designs.
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Signal Descriptions
The following signal descriptions define the IO signals.
Signal
Direction Description
clk
in
reset_n
fuart_config.baudrate[15:0]
fuart_config.data_78
in
in
in
fuart_config.par_ebl
in
fuart_config.par_pol
in
fuart_config.stop_12
in
fuart_config.tx_run
in
fuart_config.rx_run
in
rx_pin
tx_pin
fuart_tx_data[7:0]
in
out
in
fuart_tx_we
in
fuart_tx_busy
out
fuart_rx_data[7:0]
out
fuart_rx_ready
out
fuart_par_error
out
fuart_form_error
out
System clock, rising edge used only, must be at least 64 times higher than
maximum baudrate
Asynchronous system reset, active low, goes to all flip flops
Baudrate configuration value
Transmit and receive data size:
‘0’: use 7 bit data
‘1’: use 8 bit data
Parity enable:
‘0’: no parity check, no parity bit transmitted and received
‘1’: use parity check, parity bit inserted and checked
Parity polarity:
2
‘0’: use even parity
‘1’: use odd parity
This parameter is ignored when par_ebl is inactive!
Transmit and receive stop bit number:
‘0’: use and check 1 stop bit
‘1’: use and check 2 stop bits
Transmit control:
‘0’: transmitter off, ignores all inputs, outputs inactive
‘1’: transmitter is working
Receive control:
‘0’: receiver off, ignores all inputs, outputs are inactive
‘1’: receiver is working
Pin for the incoming bit stream. The inactive state is logic ‘1’
Pin for the outgoing bit stream. The inactive state is logic ‘1’
8bit data to be transmitted. For 7bit configuration, bit[7] is ignored.
Data must be valid and stable when fuart_tx_we is active.
Event for storing the tx_data in the transmit shift register and start of
transmission. It’s up to the system to not activate this input when the MC-ACTUARTF is busy.
When the transmitter is sending a byte, this status output remains active (logic
‘1’) until it is ready to send a new byte. While fuart_tx_busy is ‘1’, fuart_tx_we
mustn’t be activated.
8bit data that has been received. For 7bit configuration, bit[7] is ignored. The
data will be stable only during the active phase of fuart_rx_ready. Add a buffer
register if data should remain stable until reception of next character.
Event (active ‘1’) for signalling, that a new byte has arrived and the
fuart_rx_data is valid now.
Event (active ‘1’) for signalling, that a byte with wrong parity has been received
and aborted (it’s not visible at rx_ready)
This signal is always inactive when par_ebl is deactivated.
Event (active ‘1’) for signalling, that a byte with wrong format has been
received and aborted (it’s not visible at rx_ready)
Table 2: Core I/O Signals
2
number of ones in a byte, including parity bit is even
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Recommended Design Experience
For the source version, users should be familiar with HDL entry and Actel design flows. Users should be familiar
with Actel Libero v2.2 Integrated Design Environment (IDE) and preferably with Synplify and ModelSim.
Ordering Information
Part Number
MC-ACT-UARTF-NET
MC-ACT-UARTF-VHD
Description
Core Netlist
Core VHDL
Table 3: Core Part Numbers
The CORE is provided under license from Memec Design for use in Actel programmable logic devices. Please
contact Memec Design for pricing and more information.
Information furnished by Memec Design is believed to be accurate and reliable. Memec Design reserves the right to
change specifications detailed in this data sheet at any time without notice, in order to improve reliability, function or
design, and assumes no responsibility for any errors within this document. Memec Design does not make any
commitment to update this information.
Memec Design assumes no obligation to correct any errors contained herein or to advise any user of this text of any
correction, if such be made, nor does the Company assume responsibility for the functioning of undescribed
features or parameters. Memec Design will not assume any liability for the accuracy or correctness of any support
or assistance provided to a user.
Memec Design does not represent that products described herein are free from patent infringement or from any
other third-party right. No license is granted by implication or otherwise under any patent or patent rights of Memec
Design.
MemecCore products are not intended for use in life support appliances, devices, or systems. Use of a MemecCore
product in such application without the written consent of the appropriate Memec Design officer is prohibited.
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Datasheet Revision History
Version
Datasheet 1.0
Datasheet 1.1
Datasheet 1.2
Datasheet 1.3
February 25, 2003
Date
November 27, 2002
January 07, 2003
January 23, 2003
February 25, 2003
Description
Initial Release
Performance information modified
Modification done in section core deliverables; Added logo to footer
Modification done in section device requirements, new URL and address
inserted
Optimized for
6
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