RFXCOM RFXtrx433 Especificaciones descargar pdf (Pagina 45)

Chapter 4. Implementation 38

ISR

med

low

433Mhz reception, time control

USART, SPI reception

helping functions, RTC

data transmission, corenormal

priority

false true

PARSE CONNECT

buffer

empty?

connect?

yes

Figure 4.3.: The program core on the left and the priority table on the right.

The program core is an inﬁnite loop for basic data management and processing. It is responsible

for distributing data between the Parser, a module for command execution, and the Connect-

module, a component for the interface converting service. Whenever the buﬀer is ﬁlled by one

of the diﬀerent interrupt service routines (ISR) for data reception, the data is sent to either the

Parser or the Connect-module. This process is repeated for each interface that has been previously

opened. Due to this modular structure, the software can be easily upgraded or modiﬁed.

4.1.2. Motivation

Though the WiﬁControl 433 gateway works without serious limitations, there were some major

reasons to revise it:

• Poor WIFI reception: The printed antenna [29] performs very poorly, as the overall range

depends greatly on the surroundings. Hold in free air, the maximum range is never above

5 m.

• The USB-serial-bridge causes extra costs of approximately 8% of the total costs. In addition,

it allows only a virtual serial port and no other USB classes, such as a human interface device

(HID).

• The onboard radio module RFM22B is not working properly, so that another receiver has

to be connected to the expansion port for reliable operation.

Particularly due to the removal of the USB-serial-bridge, the printed circuit board (PCB) had to

be changed. This opportunity was taken and the PCB was completely redesigned leading to two

diﬀerent versions: the WiﬁCtrl and MiniCtrl (ﬁgure 4.4)

1 2 ... 40 41 42 43 44 45 46 47 48 49 50 ... 94 95

Sin comentarios

RFXCOM RFXtrx433 Especificaciones Pagina 45