uart don´t work tiva tm4c1294

GOOD DAY
About a month ago I wrote my problem is that I can not get the UART0 AND UART7 work simultaneously on my card C launchpad TM4C1294 tive.
The program I use is the echo.c example which should be performed by two different UART echo.c; Previously only could get to work the UART0 and the uart7 (is connected via a max232 to a computer port) nothing came.
And achieve that by typing a character is seen in the TeraTerm achieved by the port uart7, and also that of the UART0; but when trying to send more characters UART does not work and both are blocked.
bone position and test the program in the UART0 TeraTerm and makes a perfect all that want to send echo.c, but I step uart7 port and only accepts a character and then the two UART are blocked.
what will be the issue of this blockade? I tried to interrupts and I could not fix it.
thank you very much.
att
Carlos Bautista
postscript
if someone has a program that achieved while working with 2 UART (UART0, uart7, uart6) I thank you note to let me know how to configure these UART.