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8xC251TB, 8xC251TQ,
Hardware Description
Addendum to the 8xC251SA, 8xC251SB,
8xC251SP, 8xC251SQ, User’s Manual
Release Date: December 2003
Order Number: 273138-002
The 8xC251Tx may contain design defects or errors known as errata which may cause
the product to deviate from published specifications. Such errata are not covered by
Intel's warranty. Current characterized errata are available on request.
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Information in this document is provided in connection with Intel products. No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted by this document. Except as provided in Intel's Terms and Conditions of Sale for such products, Intel assumes no liability whatsoever, and Intel disclaims any express or implied warranty, relating to sale and/or use of Intel products including liability or warranties relating to fitness for a particular purpose, m
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8xC251Tx Hardware Description REVISION HISTORY: Date Revision Description November 1997 001 Initial release of this document December 2003 002 Removed references to 8XC251TA, 8XC251TP 273138-002 December 2003 iii
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8xC251Tx Hardware Description iv December 2003 273138-002
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8xC251Tx Hardware Description 8xC251TB, 8xC251TQ Hardware Description Addendum to the 8xC251SA, 8xC251SB, 8xC251SP, 8xC251SQ, User’s Manual 1.0 INTRODUCTION TO THE 8xC251Tx 1.1 Comparing the 8xC251Tx and 8xC251Sx ..................................................................... 1 2.0 SIGNAL SUMMARY 3.0 THE SECOND SERIAL I/O PORT 3.1 Overview........................................................................................................................ 7 3.2 Special Function Register
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8xC251Tx Hardware Description vi December 2003 273138-002
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8xC251Tx Hardware Description 1.0 INTRODUCTION TO THE 8xC251Tx This Hardware Description describes the 8xC251TB, 8xC251TQ (referred to collectively as the 8xC251Tx) ® embedded microcontroller, which is the newest member of the MCS 251 microcontroller family. The 8xC251Tx is pin and code compatible with the 8xC251Sx but is enhanced with the addition of new features. This document addresses the differences between the two members of the MCS 251 microcontroller family. For a detailed description
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8xC251Tx Hardware Description 2.0 SIGNAL SUMMARY Table 1. 8xC251Tx Signal Summary Address & Data Input/Output Name PLCC DIP Name PLCC DIP AD0/P0.0 43 39 P1.0/T2 2 1 AD1/P0.1 42 38 P1.1/T2EX 3 2 AD2/P0.2 41 37 P1.2/EC/RXD1 4 3 AD3/P0.3 40 36 P1.3/CEX0/TXD1 5 4 AD4/P0.4 39 35 P1.4/CEX1 6 5 AD5/P0.5 38 34 P1.5/CEX2 7 6 AD6/P0.6 37 33 P1.6/CEX3/WAIT# 8 7 AD7/P0.7 36 32 P1.7/CEX4/A17/WCLK 9 8 A8/P2.0 24 21 P3.0/RXD 11 10 A9/P2.1 25 22 P3.1/TXD 13 11 A10/P2.2 26 23 P3.4/T0 16 14 A11/P2.3 27 24 P3.51/T
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8xC251Tx Hardware Description Table 2. 8xC251Tx Signal Descriptions (Sheet 1 of 3) Signal Alternate Type Description Name Function A17 O Address Line 17. Output to memory as the 18th external address bit P1.7/CEX4/ (A17) in extended bus applications, depending on the values of bits WCLK RD0 and RD1 in configuration byte UCONFIG0 (see Chapter 4, "Device Configuration," of the 8xC251SA, 8xC251SB, 8xC251SP, 8xC251SQ Embedded Microcontroller User’s Manual (272795). See also RD# and PSEN#. A16 O
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8xC251Tx Hardware Description Table 2. 8xC251Tx Signal Descriptions (Sheet 2 of 3) Signal Alternate Type Description Name Function P3.0 I/O Port 3. This is an 8 bit, bidirectional I/O port with internal pullups RXD P3.1 TXD P3.2 INT0# P3.3 INT1# P3.4 T0 P3.5 T1 P3.6 WR# P3.7 RD#/A16 PSEN# O Program Store Enable. Read signal output to external memory. Asserted for the address range specified by the configuration byte UCONFIG0, bits RD1:0. RD# O Read. Read signal output to external memor
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8xC251Tx Hardware Description Table 2. 8xC251Tx Signal Descriptions (Sheet 3 of 3) Signal Alternate Type Description Name Function V PWR Secondary Supply Voltage 2. This supply voltage connection is pro- CC2 vided to reduce power supply noise. Connection of this spin to the +5V supply voltage is recommended. However, when using the ZX3 as a pin for pin replacement for the 8XC51FX, V can be uncon- CC2 nected without loss of compatibility (Not available on DIP). V GND Circuit Ground. Connect th
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8xC251Tx Hardware Description Table 3. Special Function Register (SFR) Map CH00000 CCAP0Hx CCAP1Hx CCAP2Hx CCAP3Hx CCAP4Hx F8 000 xxxxxxx xxxxxxx xxxxxxx xxxxxxx xxxxxxx F0 B 00000000 E8 CL CCAP0L CCAP1L CCAP2L CCAP3L CCAP4L 00000000 xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx E0 ACC 00000000 D8 CCON CMOD CCAPM0 CCAPM1 CCAPM2 CCAPM3 CCAPM4 00x00000 00xxx000 x0000000 x0000000 x0000000 x0000000 x0000000 D0 PSW PSW1 00000000 00000000 C8 T2CON T2MOD RCAP2L RCAP2H TL2 TH2 00000000 xxxxxx00 00
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8xC251Tx Hardware Description 3.0 THE SECOND SERIAL I/O PORT The second serial I/O port is functionally the same as the standard serial I/O port shared by both the 8xC251Tx and the 8xC251Sx. This section provides information about the new special function registers (SFRs) associated with the second serial port. Detailed operation and programming of the serial I/O ports can be obtained from Chapter 10 of the 8xC251SA, 8xC251SB, 8xC251SP, 8xC251SQ Embedded Microcon- troller User’s Manual (27279
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8xC251Tx Hardware Description Table 5. Second Serial I/O Port Special Function Registers Mnemonic Description Address SBUF1 Serial Buffer 1. Two separate registers comprise the SBUF1 register. Writ- 9BH ing to SBUF1 loads the transmit buffer; reading SBUF1 access the receive buffer SCON1 Serial Port Control 1. Selects the second serial I/O port operating mode. 9AH SCON1 enables and disables the receiver, framing bit error detection, multi- processor communication, automatic address recognition
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8xC251Tx Hardware Description 3.2 Special Function Register Definitions The following describes the special function registers associated with the second serial I/O port and their bit definitions. 3.2.1 SCON1 Address: 9AH Reset Value: 0000 0000B Table 6. SCON1 Special Function Register Definitions Bit Bit Number Function Mnemonic 7 FE1SM0 Framing Error Bit 1: To Select this function, set the SMOD0 bit in the BGCON register. Set by hard- ware to indicate an invalid stop bit. Cleared by softwa
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8xC251Tx Hardware Description 3.2.2 SBUF1 Address: 9BH Reset Value: xxxx xxxxB To send serial data, software writes a byte to SBUF1 and to receive serial data, software reads from SBUF1. 3.2.3 SADDR1 Address: AAH Reset Value: 0000 0000B Slave Individual Address Register1 (SADDR1) contains the device’s individual address for multiprocessor communications. 3.2.4 SADEN1 Address: BAH Reset Value: 0000 0000B Mask Byte Register 1 (SADEN1) masks bits in the SADDR1 register to form the devices given
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8xC251Tx Hardware Description 3.2.6 IE1 Address: B1H Reset Value: xxxx xxx0B Table 8. IE1 Special Function Register Definitions Bit Mne- Bit Number Function monic 7 - 1 - Reserved 0 ES1 Second serial I/O port Interrupt Enable: Setting this bit enables the second serial I/O port interrupt 3.2.7 IPH1 Address: B3H Reset Value: xxxx xxx0B Table 9. IPH1 Special Function Register Definitions Bit Mne- Bit Number Function monic 7 - 1 - Reserved 0 IPH1.0 Second serial I/O port Interrupt Priority High
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8xC251Tx Hardware Description 4.0 EXTENDED DATA FLOAT TIMING The Extended Data Float Timing feature seeks to provide a solution to users that may be using slower memory devices. Essentially, this feature extends the TRHDZ1 AC timing specification to accommodate slower memory devices which require a longer period of dead time between a data and address bus cycles. This feature is controlled by a bit in the Configuration byte (UCONFIG1). Bit 3 of UCONFIG1 in the 8xC251Tx is defined as EDF#. In
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8xC251Tx Hardware Description Table 13 shows the effect of programming EDF# and WSB#[1:0] on the extended data float timing feature as well as the insertion of wait states for region 01:. It should be noted that enabling the extended data float timing allows region 01: to have 1 or 3 wait states inserted (depending on WSB#[1:0]) but not 0 or 2 wait states. Table 13. Summary of the EDF# and WSB#[1:0] Configuration Options Extended Data Float EDF# WSB#[1:0] Wait State Timings 1 11 0 No 1 10 1
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