Philips Semiconductors Universal asynchronous receiver/transmitter (UART) DESCRIPTION The Philips Semiconductors SCC2691 Universal Asynchronous Receiver/Transmitter (UART) is a single-chip CMOS-LSI communications device that provides a full-duplex asynchronous receiver/transmitter. It is fabricated with Philips Semiconductors CMOS technology which combines the benefits of high density and low power consumption.
Philips Semiconductors Universal asynchronous receiver/transmitter (UART) PIN DESCRIPTION PIN NO. MNEMONIC MNEMONIC TYPE TYPE PLCC D0–D7 22–15 27, 25, 22–18 A0–A2 8–6 11–9 RESET INTRN X1/CLK 2006 Aug 04 NAME AND FUNCTION NAME AND FUNCTION Data Bus: Active-high 8-bit bidirectional 3-State data bus. Bit 0 is the LSB and bit 7 is the MSB.
Philips Semiconductors Universal asynchronous receiver/transmitter (UART) ABSOLUTE MAXIMUM RATINGS SYMBOL Operating ambient temperature range Storage temperature range Voltage from V to GND Voltage from any pin to ground Power Dissipation NOTES: 1. Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other condition above those indicated in the operation section of this specification is not implied.
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Philips Semiconductors Universal asynchronous receiver/transmitter (UART) AC ELECTRICAL CHARACTERISTICS SYMBOL SYMBOL PARAMETER PARAMETER Reset timing (Figure 3) Reset pulse width Bus timing (Figure 4) A0–A2 setup time to RDN, WRN low A0–A2 hold time from RDN, WRN low CEN setup time to RDN, WRN low...
SR = Status register THR = Tx holding register * See Table 6 for BRG Test frequencies in this data sheet, and “Extended baud rates for SCN2681, SCN68681, SCC2691, 2006 Aug 04 SCC2692, SCC68681 and SCC2698B” Philips Semiconductors ICs for Data Communications, IC-19, 1994.
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Philips Semiconductors Universal asynchronous receiver/transmitter (UART) values of CTUR and CTLR at any time, but the new count becomes effective only on the next start counter command following a stop counter command. If new values have not been loaded, the previous count values are preserved and used for the next count cycle.
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Philips Semiconductors Universal asynchronous receiver/transmitter (UART) In addition to the normal transmitter and receiver operation described above, the UART incorporates a special mode which provides automatic wake-up of the receiver through address frame recognition for multi-processor communications. This mode is selected by programming bits MR1[4:3] to ‘11’.
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Philips Semiconductors Universal asynchronous receiver/transmitter (UART) parity mode is programmed. In the special wake-up mode, it selects the polarity of the transmitted A/D bit. MR1[1:0] – Bits Per Character Select This field selects the number of data bits per character to be transmitted and received.
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CSR (Clock Select Register) Receiver Clock Select See Text See Table 6 for BRG Test frequencies in this data sheet, and “Extended baud rates for SCN2681, SCN68681, SCC2691, SCC2692, SCC68681 and SCC2698B” Philips Semiconductors ICs for Data Communications, IC-19, 1994. CR (Command Register)
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1 1 1 1 MPI–1X The receiver clock is always a 16X clock, except for CSR[7:4] = 1111. See “Extended baud rates for SCN2681, SCN68681, SCC2691, SCC2692, SCC68681 and SCC2698B” in application notes elsewhere in this publication CSR[7:4] – Receiver Clock Select This field selects the baud rate clock for the receiver as shown in Table 3.
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ACR[3] – Power-Down Mode Select This bit, when set to zero, selects the power-down mode. In this mode, the SCC2691 oscillator is stopped and all functions requiring this clock are suspended. The contents of all registers are saved. It is recommended that the transmitter and receiver be disabled prior...
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Philips Semiconductors Universal asynchronous receiver/transmitter (UART) to placing the SCC2691 in this mode. Note that this bit must be set to a logic 1 after reset. When the power-down mode is enabled, internal circuitry forces the X1/CLK pin to the low state and the X2 pin to the high state. If an...
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Philips Semiconductors Universal asynchronous receiver/transmitter (UART) IMR – Interrupt Mask Register The programming of this register selects which bits in the ISR cause an interrupt output. If a bit in the ISR is a ‘1’ and the corresponding bit in the IMR is a ‘1’, the INTRN output is asserted (low).
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Philips Semiconductors Universal asynchronous receiver/transmitter (UART) INTERRUPT OUTPUT INTERRUPT OUTPUT NOTES: 1. INTRN or MPO when used as interrupt outputs. 2. The test for open drain outputs is intended to guarantee switching of the output transistor. Measurement of this response is referenced from the midpoint of the switching signal, , to a point 0.5V above V...
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Philips Semiconductors Universal asynchronous receiver/transmitter (UART) (INPUT) (1X OUTPUT) (1X INPUT) 2006 Aug 04 1 BIT TIME (1 OR 16 CLOCKS) SD00092 Figure 8. Transmit Timing SD00093 Figure 9. Receive Timing Product data sheet SCC2691...
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Each read on address H‘2’ will toggle the baud rate test mode. When in the BRG test mode, the baud rates change as shown to the left. This change affects all receivers and transmitters on the DUART. See “Extended baud rates for SCN2681, SCN68681, SCC2691, SCC2692, SCC68681 and SCC2698B”...
Philips Semiconductors Universal asynchronous receiver/transmitter (UART) REVISION HISTORY Date Description 20060804 Product data sheet (9397 750 14951). Supersedes data of 1998 Sep 04 (9397 750 04358). Modifications: Ordering information: changed Version for PLCC28 from SOT261–3 to SOT261–2 Changed package outline drawing from SOT261–3 to SOT261–2.
For detailed and full information see the relevant full data sheet, which is available on request via the local Philips Semiconductors sales office. In case of any inconsistency or conflict with the short data sheet, the full data sheet shall prevail.