欢迎访问ic37.com |
会员登录 免费注册
发布采购

FM32L274-G 参数 Datasheet PDF下载

FM32L274-G图片预览
型号: FM32L274-G
PDF下载: 下载PDF文件 查看货源
内容描述: 3V集成处理器伴侣与记忆 [3V Integrated Processor Companion with Memory]
分类和应用:
文件页数/大小: 21 页 / 275 K
品牌: RAMTRON [ RAMTRON INTERNATIONAL CORPORATION ]
 浏览型号FM32L274-G的Datasheet PDF文件第1页浏览型号FM32L274-G的Datasheet PDF文件第2页浏览型号FM32L274-G的Datasheet PDF文件第3页浏览型号FM32L274-G的Datasheet PDF文件第5页浏览型号FM32L274-G的Datasheet PDF文件第6页浏览型号FM32L274-G的Datasheet PDF文件第7页浏览型号FM32L274-G的Datasheet PDF文件第8页浏览型号FM32L274-G的Datasheet PDF文件第9页  
FM32L278/L276/L274/L272 - 3V I2C Companion  
(WP0, WP1 in register 0Bh) control the protection  
setting as shown in the following table. Based on the  
setting, the protected addresses cannot be written and  
the 2-wire interface will not acknowledge any data to  
protected addresses. The special function registers  
containing these bits are described in detail below.  
Overview  
The FM32L27x family combines a serial nonvolatile  
RAM with a processor companion. The companion is  
a highly integrated peripheral including a processor  
supervisor, a comparator used for early power-fail  
warning, nonvolatile event counters, and a 64-bit  
serial number. The FM32L27x integrates these  
complementary but distinct functions that share a  
common interface in a single package. Although  
monolithic, the product is organized as two logical  
devices, the F-RAM memory and the companion.  
From the system perspective they appear to be two  
separate devices with unique IDs on the serial bus.  
Write protect addresses  
None  
WP1  
WP0  
0
0
1
1
0
1
0
1
Bottom 1/4  
Bottom 1/2  
Full array  
Processor Companion  
The FM32L27x provides the same functions as the  
FM31L27x with the exception of the real-time clock.  
This makes it easy to develop a common design that  
can either include timekeeping by using the  
FM31L27x or exclude it by using the FM32L27x. All  
other features are identical. The register address map  
is even preserved so that software can be identical.  
In addition to nonvolatile RAM, the FM32L27x  
family incorporates a highly integrated processor  
companion. It includes a low voltage reset, a  
programmable watchdog timer, battery-backed event  
counters, a comparator for early power-fail detection  
or other purposes, and a 64-bit serial number.  
Processor Supervisor  
Supervisors provide a host processor two basic  
functions: detection of power supply fault conditions  
and a watchdog timer to escape a software lockup  
condition. All FM32L27x devices have a reset pin  
(/RST) to drive the processor reset input during  
power faults (and power-up) and software lockups. It  
is an open drain output with a weak internal pull-up  
to VDD. This allows other reset sources to be wire-  
OR’d to the /RST pin. When VDD is above the  
programmed trip point, /RST output is pulled weakly  
to VDD. If VDD drops below the reset trip point  
voltage level (VTP) the /RST pin will be driven low. It  
will remain low until VDD falls too low for circuit  
operation which is the VRST level. When VDD rises  
again above VTP, /RST will continue to drive low for  
at least 100 ms (tRPU) to ensure a robust system reset  
at a reliable VDD level. After tRPU has been met, the  
/RST pin will return to the weak high state. While  
/RST is asserted, serial bus activity is locked out even  
if a transaction occurred as VDD dropped below VTP.  
A memory operation started while VDD is above VTP  
will be completed internally.  
The memory is organized as a stand-alone 2-wire  
nonvolatile memory with a standard device ID value.  
The companion functions are accessed under their  
own 2-wire device ID. This allows the companion  
functions to be read while maintaining the most  
recently used memory address. The companion  
functions are controlled by 16 special function  
registers. The event counter circuits and related  
registers are maintained by the power source on the  
VBAK pin, allowing them to operate from battery or  
backup capacitor power when VDD drops below a set  
threshold. Each functional block is described below.  
Memory Operation  
The FM32L27x is a family of products available in  
different memory sizes including 4Kb, 16Kb, 64Kb,  
and 256Kb. The family is software compatible, all  
versions use consistent two-byte addressing for the  
memory device. This makes the lowest density  
device different from its stand-alone memory  
counterparts but makes them compatible within the  
entire family.  
Figure 2 below illustrates the reset operation in  
response to the VDD voltage.  
Memory is organized in bytes, for example the 4Kb  
memory is 512 x 8 and the 256Kb memory is 32,768  
x 8. The memory is based on F-RAM technology.  
Therefore it can be treated as RAM and is read or  
written at the speed of the two-wire bus with no  
delays for write operations. It also offers effectively  
unlimited write endurance unlike other nonvolatile  
memory technologies. The 2-wire interface protocol  
is described further on page 13.  
VDD  
tRPU  
VTP  
RST  
Figure 2. Low Voltage Reset  
The memory array can be write-protected by  
software. Two bits in the processor companion area  
Rev. 3.0  
Feb. 2009  
Page 4 of 21  
 复制成功!