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OX16C950-PCC60-B 参数 Datasheet PDF下载

OX16C950-PCC60-B图片预览
型号: OX16C950-PCC60-B
PDF下载: 下载PDF文件 查看货源
内容描述: 高性能UART与128字节的FIFO [High Performance UART with 128 byte FIFOs]
分类和应用: 先进先出芯片
文件页数/大小: 49 页 / 436 K
品牌: OXFORD [ OXFORD SEMICONDUCTOR ]
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OX16C950 rev B  
OXFORD SEMICONDUCTOR LTD.  
5.6  
950 Mode  
The UART has a flexible prescaler capable of dividing the  
system clock by any value between 1 and 31.875 in steps  
of 0.125. It divides the system clock by an arbitrary value in  
“M N/8” format, where M and N are 5 and 3-bit binary  
numbers programmed in CPR[7:3] and CPR[2:0]  
respectively. This arrangement offers a great deal of  
flexibility when choosing an input clock frequency to  
synthesize arbitrary baud rates. The default division value  
is 4 to provide backward compatibility with 16C650  
devices.  
The additional features offered in OX16C950 (950 mode)  
generally only apply when the UART is in Enhanced mode  
(EFR[4]=’1’). Provided FCR[0] is set, in Enhanced mode  
the FIFO size is 128 regardless of the state of FIFOSEL.  
Note that 950 mode configuration is identical to that of 650  
mode, however additional 950 specific features are  
enabled using the Additional Control Register ‘ACR’ (see  
section 15.3). In addition to larger FIFOs and higher baud  
rates, the enhancements of the 16C950 over the 16C654  
are:  
The user may apply an external 1x (or Nx) clock for the  
transmitter and receiver to the RI# and DSR# pin  
respectively. The transmitter clock may be asserted on the  
DTR# pin. The external clock options are selected through  
the CKS register (offset 0x02 of ICR).  
Selectable arbitrary trigger levels for the receiver and  
transmitter FIFO interrupts  
Improved automatic flow control using selectable  
arbitrary thresholds  
DSR#/DTR# automatic flow control  
Transmitter and receiver can be optionally disabled  
Software reset of device  
It is also possible to define the over-sampling rate used by  
the transmitter and receiver clocks. The 16C450/16C550  
and compatible devices employ 16 times over-sampling,  
i.e. There are 16 clock cycles per bit. However, OX16C950  
can employ any over-sampling rate from 4 to 16 by  
programming the TCR register. This allows the data rates  
to be increased to 460.8 Kbps using a 1.8432MHz clock, or  
15 Mbps using a 60 MHz clock. The default value after a  
reset for this register is 0x00, which corresponds to a 16  
cycle sampling clock. Writing 0x01, 0x02 or 0x03 will also  
result in a 16 cycle sampling clock. To program the value to  
any value from 4 to 15 it is necessary to write this value  
into TCR i.e. to set the device to a 13 cycle sampling clock  
it would be necessary to write 0x0D to TCR. For further  
information see sections 14.3.  
Readable FIFO fill levels  
Optional generation of an RS-485 buffer enable signal  
Four-byte device identification (0x16C95003)  
Readable status for automatic in-band and out-of-  
band flow control  
External 1x clock modes (see section 14.4)  
Flexible “M N/8” clock prescaler (see section 14.2)  
Programmable sample clock to allow data rates up to  
15 Mbps (see section 14.3)  
9-bit data mode  
The 950 trigger levels are enabled when ACR[5] is set (bits  
4 to 7 of FCR are ignored). Then arbitrary trigger levels can  
be defined in RTL, TTL, FCL and FCH registers (see  
section 15). The Additional Status Register (‘ASR’) offers  
flow control status for the local and remote transmitters.  
FIFO levels are readable using RFL and TFL registers.  
The OX16C950 also offers 9-bit data frames for multi-drop  
industrial applications.  
Data Sheet Revision 1.2  
Page 14