Hardware Design SIM800L (SIMCom) - 32
| Manufacturer | SIMCom |
| Description | Quad-band GSM/GPRS module, that works on frequencies GSM850MHz, EGSM900MHz, DCS1800MHz and PCS1900MHz |
| Pages / Page | 70 / 32 — Smart Machine Smart Decision MODULE DTE 10K RXD TXD TXD RXD. 10K Figure … |
| Revision | 1.09 |
| File Format / Size | PDF / 2.8 Mb |
| Document Language | English |
Smart Machine Smart Decision MODULE DTE 10K RXD TXD TXD RXD. 10K Figure 21 : Diode isolation circuit
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Smart Machine Smart Decision MODULE DTE 10K RXD TXD TXD RXD
10K Figure 21 : Diode isolation circuit
Note: please make sure the minimum of client high limit should be less than 2.8V minus the diode drop.
If the voltage of UART is 5V, the following reference circuits are recommended: Figure 22: TX level matching circuit Figure 23: RX level matching circuit
Note: When Fig 22 and Fig 23are used for electrical level isolation, if customers use serial port to upgrade
SW, please note VDDEXT has no voltage output during the upgrading process, LDO output could be used as
VDDEXT in the figure, upgrading through USB port is recommended. SIM800L_Hardware_Design_V1.00 32 2013-08-20
10K Figure 21 : Diode isolation circuit
Note: please make sure the minimum of client high limit should be less than 2.8V minus the diode drop.
If the voltage of UART is 5V, the following reference circuits are recommended: Figure 22: TX level matching circuit Figure 23: RX level matching circuit
Note: When Fig 22 and Fig 23are used for electrical level isolation, if customers use serial port to upgrade
SW, please note VDDEXT has no voltage output during the upgrading process, LDO output could be used as
VDDEXT in the figure, upgrading through USB port is recommended. SIM800L_Hardware_Design_V1.00 32 2013-08-20
