收藏本站
TRF7970A
SLOS743K – AUGUST 2011 – REVISED APRIL 2014
www.ti.com
6.10.6 Direct Mode
Direct mode allows the user to configure the reader in one of two ways. Direct Mode 0 (bit 6 = 0, as
defined in ISO Control register) allows the user to use only the front-end functions of the reader,
bypassing the protocol implementation in the reader. For transmit functions, the user has direct access to
the transmit modulator through the MOD pin (pin 14). On the receive side, the user has direct access to
the subcarrier signal (digitized RF envelope signal) on I/O_6 (pin 23).
Direct Mode 1 (bit 6 = 1, as defined in ISO Control register) uses the subcarrier signal decoder of the
selected protocol (as defined in ISO Control register). This means that the receive output is not the
subcarrier signal but the decoded serial bit stream and bit clock signals. The serial data is available on
I/O_6 (pin 23) and the bit clock is available on I/O_5 (pin 22). The transmit side is identical; the user has
direct control over the RF modulation through the MOD input. This mode is provided so that the user can
implement a protocol that has the same bit coding as one of the protocols implemented in the reader, but
needs a different framing format.
To select direct mode, the user must first choose which direct mode to enter by writing B6 in the ISO
Control register. This bit determines if the receive output is the direct subcarrier signal (B6 = 0) or the
serial data of the selected decoder. If B6 = 1, then the user must also define which protocol should be
used for bit decoding by writing the appropriate setting in the ISO Control register.
The reader actually enters the direct mode when B6 (direct) is set to 1 in the chip status control register.
Direct mode starts immediately. The write command should not be terminated with a stop condition (see
communication protocol), because the stop condition terminates the direct mode and clears B6. This is
necessary as the direct mode uses one or two I/O pins (I/O_6, I/O_5). Normal parallel communication is
not possible in direct mode. Sending a stop condition terminates direct mode.
Figure 6-27 shows the different configurations available in direct mode.
?
?
?
In mode 0, the reader is used as an AFE only, and protocol handling is bypassed.
In mode 1, framing is not done, but SOF and EOF are present. This allows for a user-selectable
framing level based on an existing ISO standard.
In mode 2, data is ISO-standard formatted. SOF, EOF, and error checking are removed, so the
microprocessor receives only bytes of raw data through a 127-byte FIFO.
Analog Front End (AFE)
Direct Mode 0:
Raw RF Sub-Carrier
Data Stream
ISO Encoders/Decoders
14443A
14443B
15693
FeliCa
Direct Mode 1:
Raw Digital ISO Coded
Data Without
Protocol Frame
Packetization/Framing
ISO Mode:
Full ISO Framing
and Error Checking
Microcontroller
(Typical Mode)
Figure 6-27. User-Configurable Modes
The steps to enter Direct Mode are listed below, using SPI with SS communication method only as one
example, as Direct Modes are also possible with parallel and SPI without SS. The must enter Direct Mode
0 to accommodate non-ISO standard compliant card type communications. Direct Mode can be entered at
any time, so in the event a card type started with ISO standard communications, then deviated from the
standard after being identified and selected, the ability to go into Direct Mode 0 becomes very useful.
42
Detailed Description
Submit Documentation Feedback
Product Folder Links: TRF7970A
Copyright ? 2011–2014, Texas Instruments Incorporated
发布紧急采购，3分钟左右您将得到回复。

采购需求

(若只采购一条型号，填写一行即可)

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

*型号 *数量 厂商 批号 封装
添加更多采购

我的联系方式

*
*
*
相关PDF资料
TRM-418-LT TRANSCEIVER RF 418MHZ LT SERIES
TRM-900-NT RF TXRX 915MHZ NT SERIES
TRX08GVP2540 TXRX OPT SCFF 8.5GB/S 850NM
TS-320240BRNO TCH PANEL 140X104 RESISTIVE MONO
TS-TFT3.5Z TOUCH PANEL 140X1.4.0 TFT
TS3-75B3 SENSOR THERMAL MOXIE NTC 75C
TSL26711FN IC PROXIMITY DETECTOR 6-DFN
TSOP57238TT1 IC IR RCVR MODULE 38KHZ
相关代理商/技术参数
TRF7970ARHBR 功能描述:IC RFID/NFC AFE 13.56MHZ 32QFN RoHS:是 类别:RF/IF 和 RFID >> RFID IC 系列:- 其它有关文件:CR14 View All Specifications 标准包装:1 系列:- RF 型:收发器 频率:13.56MHz 特点:ISO14443-B 封装/外壳:16-SOIC（0.154"，3.90mm 宽） 供应商设备封装:16-SO 包装:Digi-Reel® 其它名称:497-5719-6
TRF7970ARHBT 功能描述:IC RFID/NFC AFE 13.56MHZ 32QFN RoHS:是 类别:RF/IF 和 RFID >> RFID IC 系列:- 其它有关文件:CR14 View All Specifications 标准包装:1 系列:- RF 型:收发器 频率:13.56MHz 特点:ISO14443-B 封装/外壳:16-SOIC（0.154"，3.90mm 宽） 供应商设备封装:16-SO 包装:Digi-Reel® 其它名称:497-5719-6
TRF7970ATB 功能描述:RFID应答器 TRF7970A Target Brd RoHS:否 制造商:Murata 存储容量:512 bit 工作温度范围:- 40 C to + 85 C 安装风格:SMD/SMT 封装 / 箱体: 封装:Reel
TRF79A6AA17LB000 制造商:Opnext 功能描述:XFP FORM FACTOR - Boxed Product (Development Kits)
TRF79A6AA18LB000 制造商:Opnext 功能描述:XFP FORM FACTOR - Boxed Product (Development Kits)
TRF79A6AA19LB000 制造商:Opnext 功能描述:XFP FORM FACTOR - Boxed Product (Development Kits)
TRF79A6AA20LB000 制造商:Opnext 功能描述:XFP FORM FACTOR - Boxed Product (Development Kits)
TRF79A6AA21LB000 制造商:Opnext 功能描述:XFP FORM FACTOR - Boxed Product (Development Kits)