参数资料
| 型号： | MAX6957ANI |
| 厂商： | Maxim Integrated |
| 文件页数： | 10/25页 |
| 文件大小： | 0K |
| 描述： | IC DRIVER LED PORT 20/28 28-DIP |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 14 |
| 显示器类型： | LED |
| 配置： | 7、16、20 段 |
| 接口： | 4 线串行 |
| 电流 - 电源： | 180µA |
| 电源电压： | 2.5 V ~ 5.5 V |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 通孔 |
| 封装/外壳： | 28-DIP（0.300"，7.62mm） |
| 供应商设备封装： | 28-PDIP |
| 包装： | 管件 |
4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and
28-Port LED Display Driver and I/O Expander
It is acceptable to clock more than 16 bits into the
MAX6957 between taking CS low and taking CS high
again. In this case, only the last 16 bits clocked into the
MAX6957 are retained.
Reading Device Registers
Any register data within the MAX6957 may be read by
sending a logic high to bit D15. The sequence is:
1) Take SCLK low.
2) Take CS low (this enables the internal 16-bit shift
register).
3) Clock 16 bits of data into DIN—D15 first to D0 last.
D15 is high, indicating a read command and bits
D14 through D8 containing the address of the regis-
ter to be read. Bits D7–D0 contain dummy data,
which is discarded.
4) Take CS high (either while SCLK is still high after
clocking in the last data bit, or after taking SCLK
low), positions D7 through D0 in the Shift register
are now loaded with the register data addressed by
bits D1 through D8.
5) Take SCLK low (if not already low).
6) Issue another read or write command (which can
be a No-Op), and examine the bit stream at DOUT;
the second 8 bits are the contents of the register
addressed by bits D1 through D8 in step 3.
Initial Power-Up
On initial power-up, all control registers are reset, cur-
rent registers are set to minimum value, and the
MAX6957 enters shutdown mode ( Table 4).
LED Current Control
LED segment drive current can be set either globally or
individually. Global control simplifies the operation
when all LEDs are set to the same current level,
because writing one register, the Global Current regis-
ter, sets the current for all ports configured as LED seg-
ment drivers. It is also possible to individually control
the current drive of each LED segment driver.
Individual/global brightness control is selected by set-
ting the configuration register I bit (Table7). The global
current register (0x02) data are then ignored, and seg-
ment currents are set using register addresses 0x12
through 0x1F (Tables 10, 11, and 12). Each segment is
controlled by a nibble of one of the 16 current registers.
Transition (Port Data Change) Detection
Port transition detection allows any combination of the
seven ports P24–P30 to be continuously monitored for
changes in their logic status (Figure 6). A detected
change is flagged on port P31, which is used as an
active-high interrupt output (INT). Note that the
MAX6957 does not identify which specific port(s)
caused the interrupt, but provides an alert that one or
more port levels have changed.
The mask register contains 7 mask bits that select
which of the seven ports P24–P30 are to be monitored
(Table 13). Set the appropriate mask bit to enable that
port for transition detect. Clear the mask bit if transitions
on that port are to be ignored. Transition detection
works regardless of whether the port being monitored is
set to input or output, but generally it is not particularly
useful to enable transition detection for outputs.
Port P31 must be configured as an output in order to
work as the interrupt output INT when transition detec-
tion is used. Port P31 is set as output by writing bit D7
= 0 and bit D6 = 1 to the port configuration register
(Table 1).
To use transition detection, first set up the mask regis-
ter and configure port P31 as an output, as described
above. Then enable transition detection by setting the
M bit in the configuration register (Table 8). Whenever
the configuration register is written with the M bit set,
the MAX6957 updates an internal 7-bit snapshot regis-
ter, which holds the comparison copy of the logic states
of ports P24 through P30. The update action occurs
regardless of the previous state of the M bit, so that it is
not necessary to clear the M bit and then set it again to
update the snapshot register.
When the configuration register is written with the M bit
set, transition detection is enabled and remains
enabled until either the configuration register is written
with the M bit clear, or a transition is detected. The INT
output port P31 goes low, if it was not already low.
Once transition detection is enabled, the MAX6957
continuously compares the snapshot register against
the changing states of P24 through P31. If a change on
any of the monitored ports is detected, even for a short
time (like a pulse), INT output port P31 is latched high.
The INT output is not cleared if more changes occur or
if the data pattern returns to its original snapshot condi-
tion. The only way to clear INT is to access (read or
write) the transition detection mask register (Table 13).
Transition detection is a one-shot event. When INT has
been cleared after responding to a transition event,
transition detection is automatically disabled, even
though the M bit in the configuration register remains
set (unless cleared by the user). Reenable transition
detection by writing the configuration register with the
M bit set to take a new snapshot of the seven ports,
P24 to P30.
10
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| MAX6957ANI+ | 功能描述:LED显示驱动器 2.5-5.5V 20/28Port LED Display Driver RoHS:否 制造商:Micrel 数位数量:5 片段数量: 安装风格:SMD/SMT 封装 / 箱体:PLCC-44 工作电源电压:4.75 V to 11 V 最大电源电流:10 mA 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装:Tube |
| MAX6957APL | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX6957ATL | 功能描述:LED显示驱动器 RoHS:否 制造商:Micrel 数位数量:5 片段数量: 安装风格:SMD/SMT 封装 / 箱体:PLCC-44 工作电源电压:4.75 V to 11 V 最大电源电流:10 mA 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装:Tube |
| MAX6957ATL+ | 功能描述:LED显示驱动器 2.5-5.5V 20/28Port LED Display Driver RoHS:否 制造商:Micrel 数位数量:5 片段数量: 安装风格:SMD/SMT 封装 / 箱体:PLCC-44 工作电源电压:4.75 V to 11 V 最大电源电流:10 mA 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装:Tube |
| MAX6957ATL+T | 功能描述:LED显示驱动器 2.5-5.5V 20/28Port LED Display Driver RoHS:否 制造商:Micrel 数位数量:5 片段数量: 安装风格:SMD/SMT 封装 / 箱体:PLCC-44 工作电源电压:4.75 V to 11 V 最大电源电流:10 mA 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装:Tube |
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